Lower abdominal and back pain: identifying and understanding the causes

28. Juli 2026 ca. 23 Minuten

What to expect in this article

1. Why do the lower abdomen and back often hurt at the same time?
2. What could be causing it—diverticular disease, irritable bowel syndrome, or endometriosis?
3. How can you monitor your pain—and when is it an emergency?
4. Diverticular disease: When does pain come from the lower left abdomen?
5. Endometriosis: Why lower abdominal pain radiates to the back
6. What if no physical cause can be found?
7. How can a gut flora analysis with mybody® help put things in perspective?
8. What a microbiome test can and cannot do
Conclusion
Frequently asked questions
Sources

Why do the lower abdomen and back often hurt at the same time?

Pain that starts in the lower abdomen and is also felt in the back usually does not mean that two conditions are present at the same time. It usually means that one condition is causing pain that radiates—in other words, pain felt in several places even though it has just one origin.

The Institute for Quality and Efficiency in Health Care (IQWiG) explicitly describes this radiating pain in connection with endometriosis. According to the IQWiG, the pain can “vary in intensity and radiate to the lower abdomen, back, and legs” (IQWiG, 2024).

What Radiating Pain Means for Finding the Cause

Radiating pain makes it harder to identify the cause because the location where it is felt and where it originates may differ. Those who experience the back as the main source of discomfort often look first to the spine for the cause—and overlook what is happening in the lower abdomen.

The reverse is also true: When focusing on the lower abdomen, it’s easy to think of the intestines. But with lower abdominal pain that radiates elsewhere, that is just one of several possibilities—and not even the most likely one in women of childbearing age.

Why pain location alone does not provide a diagnosis

The location of the pain offers an initial clue, but not an answer. According to IQWiG (2026), diverticular disease typically causes pain in the lower left abdomen—but left-sided lower abdominal pain is by no means proof of diverticula.

The pattern is more informative: When does the pain occur, how long does it last, what changes it, and what other symptoms accompany it? You can document this pattern yourself before visiting your doctor.

This article specifically covers the combination of lower abdominal pain and back pain. If you’re more concerned with a dull feeling of pressure without clear pain, you’ll find guidance in the article Abdominal pressure; if the symptoms occur in the upper abdomen and directly after meals, Stomach pain after eating is the right article.

What could be causing it—diverticula, IBS, or endometriosis?

When lower abdominal pain is accompanied by back pain, three explanations are especially common: diverticular disease, irritable bowel syndrome, and endometriosis. Two originate in the intestines, one does not—and that one is often considered too late in women.

The following overview compares the three possibilities using the same criteria. It is based exclusively on information from IQWiG. Where the sources used do not provide information, this is explicitly stated in the table—nothing is estimated here.

The table shows a gap that should be acknowledged: The IQWiG pages used here do not describe pain radiating to the back for diverticular disease or irritable bowel syndrome. Back pain is explicitly described as radiating in endometriosis.

This does not rule anything out, but it does suggest an order of priority: If lower abdominal pain and back pain regularly occur together in a woman of childbearing age, gynecological assessment should come first - not at the end of a lengthy bowel investigation.

How do you monitor your pain - and when is it an emergency?

Before monitoring your symptoms, check for warning signs. Some symptom patterns call for prompt medical help, making waiting and keeping a record the wrong response.

If none of these warning signs are present and symptoms have lasted for weeks or months, structured self-monitoring can help. It does not replace an examination, but it makes the doctor's appointment much more focused.

Four questions are enough. Record your answers over two to four weeks - by hand or in a notes app; the format is secondary. What matters is bringing the information to your appointment rather than trying to reconstruct it from memory.

These four questions help you prepare for a doctor's appointment; they are not for self-diagnosis. They organize your observations so the doctor can get to the right test more quickly.

Diverticular disease: When does pain come from the lower left abdomen?

Diverticular disease is the most common intestinal cause to consider when someone has pain in the lower left abdomen. It develops in pouches in the intestinal wall, which become more common with age.

IQWiG (2026) defines them as follows: “Diverticula are pouches in the intestinal lining: At the affected areas, the inner wall of the intestine bulges outward through weak spots in the intestinal muscles.”

How common are diverticula in the colon?

Diverticula are very common with increasing age. About 13% of people under 50 have diverticula, compared with about 50% of people over 70 (IQWiG, 2026).

However, having diverticula does not mean having symptoms. Only when they cause symptoms is it called diverticular disease - and only when there is inflammation is it called diverticulitis.

About 1% of all people with diverticula develop diverticulitis within 10 years (IQWiG, 2026). For most people affected, a finding of “diverticula” is therefore no cause for concern.

What other symptoms are associated with diverticular disease?

In addition to pain in the left lower abdomen, IQWiG (2026) says that “bloating, constipation or diarrhea may occur.” The symptoms are therefore similar to those of irritable bowel syndrome—which is one reason the two are often confused in everyday life.

The distinction becomes clear when inflammation develops. According to IQWiG (2026), “sudden dull pain in the lower abdomen occurs, accompanied by a mild fever.” Fever is not part of irritable bowel syndrome—it is a sign that needs medical assessment.

Endometriosis: Why pelvic pain radiates to the back

In women, endometriosis is the best-supported explanation when lower abdominal pain occurs together with back pain. It is not a bowel condition—but that is precisely why it belongs in this article.

IQWiG (2024) describes the condition as follows: “In endometriosis, tissue similar to the uterine lining is found in the wall of the uterus or outside the uterus.”

What does endometriosis pain feel like?

IQWiG (2024) clearly identifies the main symptom: “The main symptom of endometriosis is pelvic pain. It often occurs together with menstrual bleeding, but also during or after sexual intercourse.”

The pain is “often experienced as cramping and can be accompanied by nausea, vomiting and diarrhea” (IQWiG, 2024). These accompanying symptoms explain why many people affected initially suspect a gastrointestinal cause.

The IQWiG’s (2024) wording is particularly important when it comes to back pain: the pain “can vary in intensity and radiate to the lower abdomen, back and legs.” This is exactly the pattern described by the symptoms discussed in this article.

How common is endometriosis in cases of chronic lower abdominal pain?

Studies show that up to 10% of all women of childbearing age have endometriosis (IQWiG, 2024). This makes it a common condition, not a rare exception.

The second figure is even more telling. Among women with chronic lower abdominal pain, around 50% are thought to have endometriosis (IQWiG, 2024). This means that when lower abdominal pain persists, endometriosis is statistically not a fringe explanation, but one of the first possibilities to investigate.

In practice, this means that if you’re a woman who has had lower abdominal pain for months, radiating to your back and clearly linked to your cycle, you should see a gynecologist—not get a stool test or change your diet.

The connection to the menstrual cycle is the key distinguishing feature compared with intestinal causes. Irritable bowel syndrome is not linked to the cycle, and neither are diverticula.

What if no physical cause can be found?

Not every examination leads to a finding. If pain persists without an identifiable physical cause, two possibilities may be considered: irritable bowel syndrome and functional physical symptoms.

Irritable bowel syndrome: common, distressing, but not dangerous

Estimates suggest that about 10 to 20 out of every 100 people have irritable bowel syndrome (IQWiG, 2023). According to the IQWiG (2023), typical symptoms include “persistent abdominal or lower abdominal pain, cramps, and changes in bowel movements.”

Important context: According to the IQWiG (2023), irritable bowel syndrome is not dangerous, and most people with a mild form do well without treatment. This reassurance belongs in the text just as much as the warning signs in Chapter 3.

According to the IQWiG (2023), possible causes of irritable bowel syndrome include hypersensitive intestinal nerves, disorders of the intestinal muscles, changes in the gut flora, and inflammation of the intestinal wall. The term “possible” is used deliberately—the exact trigger is not known.

Functional physical symptoms: real, even without findings

According to the IQWiG (2026), functional physical symptoms are said to occur “when physical symptoms are present without a physical cause, such as inflammation or an injury, being found.”

The IQWiG (2026) explicitly clarifies: “However, this does not mean that the symptoms are imagined or that nothing can be done.” So a lack of findings is not a judgment on whether the pain is real.

Estimates suggest that about 10% of the population experiences symptoms for which no clear explanation can be found (IQWiG, 2026). These explicitly include “stomach and intestinal problems such as nausea, vomiting, bloating, diarrhea, and constipation.”

IQWiG (2026) also points to the link with stress: “Stress, for example, can disrupt bowel function. This can lead to diarrhea, bloating, or constipation.” This explains why symptoms can worsen during stressful periods of life, even when nothing has changed physically.

From notes to a structured conversation with your doctor

Good documentation is especially valuable when there is no clear finding. It prevents every new appointment from starting from scratch and makes patterns visible that might otherwise get lost in the conversation.

The main lesson here is this: What matters is not how many notes you make, but how well they are organized. Location, radiation, triggers, and duration are more than enough.

How can a gut flora test from mybody® help put things into context?

A gut flora test is useful when medical evaluation is already underway or complete and you also want to understand the composition of your gut flora. It complements diagnostic testing; it does not replace it.

The relevant connection is narrowly defined. According to IQWiG (2023), changes in gut flora are among the factors suspected of contributing to irritable bowel syndrome - suspected, not proven. This is exactly where a microbiome test can provide additional information.

A microbiome test is no substitute for a diagnosis - it helps put what is happening in your gut into context. It shows the composition of your gut flora at a particular point in time, providing a starting point for conversations about diet and daily life.

mybody® (MYBODY Lab GmbH) offers two gut microbiome tests that differ in scope. Both use a stool sample that you collect at home and are analyzed in an ISO-certified laboratory.

Those who initially want only an overview of their gut flora composition will find a more introductory option in the Basic version. It covers fewer areas of analysis, but uses the same sample type and offers the same laboratory quality.

All pricing and service details are current as of July 28, 2026. Prices and processing times may change; the relevant product page always takes precedence.

What a microbiome test can and cannot do

A microbiome test describes the composition of your gut flora. It does not answer the question of why pain in the lower abdomen radiates to the back.

This is not a weakness of the method, but its definition. A stool sample shows bacteria - it does not show bulges in the intestinal wall, tissue outside the uterus, or inflammation in the abdominal cavity.

That’s why the following applies to all three causes discussed in this article: diverticular disease, endometriosis, and irritable bowel syndrome cannot be diagnosed through a gut microbiome analysis. Irritable bowel syndrome requires a medical assessment, endometriosis requires a gynecological evaluation, and diverticular disease requires a medical diagnosis.

The reverse is also true: a normal microbiome result does not rule out any disease. If symptoms persist, medical evaluation is still necessary, regardless of what a test report says.

It’s also important to be honest: mybody® does not offer a dedicated test for lactose or fructose intolerance. The hydrogen breath test is the medical standard for lactose intolerance: according to IQWiG (2024), after drinking a lactose solution, the hydrogen content of the breath is measured several times.

Conclusion

Lower abdominal pain that radiates to the back is a pattern with several possible explanations. The main intestinal causes to consider are diverticular disease and irritable bowel syndrome; outside the intestines, endometriosis is a key possibility for women.

The clearest figures point to a gynecological cause: According to IQWiG (2024), around 50% of women with chronic lower abdominal pain are thought to have endometriosis. The connection with back pain is explicitly described in this context.

Specifically recommended: Check for warning signs first. Seek medical help promptly if you have severe abdominal pain with a hard abdomen, fever, nausea, a racing heart, and general weakness. Do the same if you have blood in your stool, significant weight loss, or pale skin.

If none of these apply, keep a record for two to four weeks of where the pain occurs, where it radiates, what triggers it, and how long it lasts, then take your notes to your doctor’s office. A gut microbiome analysis can accompany this process, but it cannot replace it.

Frequently asked questions

Sources

1. IQWiG / gesundheitsinformation.de: Diverticular disease and diverticulitis (2026) — gesundheitsinformation.de
2. IQWiG / gesundheitsinformation.de: Endometriosis (2024) — gesundheitsinformation.de
3. IQWiG / gesundheitsinformation.de: Irritable bowel syndrome (2023) — gesundheitsinformation.de
4. IQWiG / gesundheitsinformation.de: Unexplained physical symptoms (functional physical symptoms) (2026) — gesundheitsinformation.de
5. IQWiG / gesundheitsinformation.de: Lactose intolerance (milk sugar intolerance) (2024) — gesundheitsinformation.de

All information about diverticula, diverticulitis, and associated warning signs is based on [1]. Statements about endometriosis, pain radiating to the back, and frequencies of up to 10% and approximately 50% are from [2]. Information about irritable bowel syndrome, its typical symptoms, and the warning signs of weight loss, blood in the stool, fever, and paleness is from [3]. The classification of functional physical complaints follows [4], and the note about hydrogen breath testing for lactose intolerance follows [5]. Product information comes from the mybody® product pages, accessed on July 28, 2026. All other studies mentioned in the text are cited at the relevant point with author, journal, and year.