Why might my side hurt when I pee or poop?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Side pain during urination or bowel movements is often caused by the close anatomical relationship between the bladder and colon, where irritation in one organ can trigger discomfort in the other. Nerve compression or irritation in the lower back can also refer pain to the pelvic region during these activities.

Because these symptoms can stem from multiple sources—ranging from urinary tract issues to gastrointestinal conditions or nerve problems—identifying the root cause quickly matters. Taking a free, instant, online symptom check can help you pinpoint likely causes based on your specific symptoms and guide your next steps, whether that means self-care, seeing a primary care doctor, or consulting a specialist.

Reviewed for medical accuracy: 07/14/2026

Important Next Steps

Learn what causes side pain with urination Discover if side pain needs urgent care Find possible causes of side pain See OTC options for side pain Find doctors for pain during urination Understand home remedies for side pain Find if side pain suggests serious illness

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Explanation

When you feel pain in your side while peeing or pooping, it could be due to a few reasons. One possibility is something called cross-organ sensitization, where the bladder and colon affect each other. This means that if one is irritated, it can cause pain in the other. Another reason could be related to the nerves in your lower back. These nerves, when irritated, can cause pain during activities like peeing or pooping.

Possible Causes:

Cross-organ Sensitization: The bladder and colon can influence each other's pain signals, making one organ's irritation felt in the other.
Nerve Issues: Problems in the nerves of the lower back, called lumbosacral radicular pain, can cause discomfort during urination or defecation.

If you experience persistent or severe pain, it is important to consult a healthcare professional for proper diagnosis and management. You can start by using our free AI symptom checker to help identify what might be causing your symptoms.

(References)

Grundy L, & Brierley SM. (2018). Cross-organ sensitization between the colon and bladder. American journal of physiology. Gastrointestinal and liver physiology, 29146678.
Haddad R, Hentzen C, Le Breton F, Sheikh Ismael S, & Amarenco G. (2019). Lumbosacral radicular pain during micturition, defecation .... European journal of pain (London, England), 30697909.
Verhamme KM, Sturkenboom MC, Stricker BH, & Bosch R. (2008). Drug-induced urinary retention: incidence, management .... Drug safety, 18422378.

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