Lower belly pain has dozens of possible causes, ranging from something as minor as gas or a pulled muscle to something that needs same-day medical attention like appendicitis. Where exactly the pain sits, how it started, and what other symptoms came with it are the biggest clues to what’s going on. Here’s a breakdown of the most common reasons your lower abdomen might be hurting and how to tell them apart.
Pain on the Right Side
The most well-known cause of lower right abdominal pain is appendicitis. Your appendix branches off the large intestine on the right side, and when it becomes inflamed, it produces a distinctive pain pattern: it usually starts as a vague ache near your belly button, then migrates to the lower right over the course of 12 to 24 hours, becoming sharper and more constant as it settles. Moving, coughing, or sneezing makes it worse. You may also lose your appetite, feel nauseous, develop a low fever, or notice you can’t pass gas.
If the pain follows that pattern, take it seriously. An inflamed appendix can burst, spreading infection into the abdominal cavity. That said, not all right-sided pain is appendicitis. A kidney stone on the right side, an ovarian cyst, or even constipation that’s built up in the part of the colon on that side can produce similar discomfort.
Pain on the Left Side
Lower left abdominal pain is often tied to the colon. Diverticulitis is one of the most common culprits, especially in adults over 40. Small pouches called diverticula can form in the colon wall, and they develop most frequently on the lower left side. When one of these pouches gets inflamed or infected, it causes steady, sometimes severe pain in that area, often alongside fever, nausea, and changes in bowel habits.
Irritable bowel syndrome (IBS) can cause pain in the same spot, which makes the two easy to confuse. Both involve abdominal pain and irregular bowel habits, and both tend to produce tenderness in the lower abdomen on exam. The key difference is chronicity: IBS pain tends to come and go over months or years, often tied to stress or certain foods, while diverticulitis usually hits more acutely with fever and a clear worsening over days.
Pain in the Center or Below the Belt Line
When the pain is low and central, sitting right above the pubic bone, the bladder and urinary tract are the usual suspects. A urinary tract infection causes a burning sensation when you urinate along with increased urgency and frequency. The pain typically stays in the lower abdomen around the pubic area. Kidney stones, by contrast, produce a sharper, stabbing pain that usually hits more toward the back or side of your lower torso, though it can radiate forward. Blood in your urine points more toward a kidney stone than a simple UTI.
A chronic condition called interstitial cystitis can also cause persistent pain in this region. It produces bladder pressure and urinary urgency that flares in response to triggers like stress, prolonged sitting, exercise, sexual activity, and (in women) menstruation. The symptoms wax and wane over time rather than arriving all at once.
Reproductive Causes
In women, lower belly pain on one side often traces back to the ovaries. Ovulation itself can cause a brief, sharp twinge mid-cycle, known as mittelschmerz, that alternates sides month to month. Ovarian cysts, which are fluid-filled sacs, can produce a dull ache or sudden sharp pain if they rupture or twist. Endometriosis, where tissue similar to the uterine lining grows outside the uterus, causes pain that often worsens during periods but can become constant over time.
An ectopic pregnancy, where a fertilized egg implants outside the uterus (usually in a fallopian tube), causes lower abdominal pain that can become severe quickly. If there’s any chance you could be pregnant and you’re experiencing one-sided pelvic pain, that needs urgent evaluation. When doctors suspect a reproductive cause, ultrasound is the standard first imaging step, whether or not a pregnancy test is positive.
In men, lower abdominal pain can come from prostatitis (inflammation of the prostate), which produces a deep ache in the pelvis along with urinary symptoms. Testicular torsion, where the testicle twists on its blood supply, causes sudden, severe pain that can radiate up into the lower abdomen. That’s a surgical emergency.
Muscle Strain and Hernias
Not all lower belly pain comes from inside the abdomen. A strained abdominal or groin muscle can cause a dull ache or burning sensation, especially when you stand. You’ll typically remember the moment it happened, sometimes even feeling a pop, with immediate pain that can linger for days or weeks.
An inguinal hernia, where fatty tissue or a loop of intestine pushes through a weak spot in the abdominal wall into the groin, produces very similar symptoms. The distinguishing feature is a visible or palpable lump in the groin area, something you won’t have with a simple strain. You may be able to push a hernia back in when you lie down, but it will return when you stand because the hole in the muscle wall doesn’t heal on its own. The serious risk with a hernia is strangulation, where the protruding tissue gets trapped and loses its blood supply, causing sudden severe pain, nausea, and vomiting.
Constipation and Gas
The most common and least dramatic cause of lower abdominal pain is simply a backup in the digestive system. Constipation can produce cramping, bloating, and a feeling of fullness or pressure across the lower belly. Trapped gas tends to cause sharper, more localized pain that shifts around and eventually resolves once the gas moves. If your pain came on gradually, you haven’t had a bowel movement in a few days, and you’re feeling bloated, this is likely where to start.
When Lower Belly Pain Is an Emergency
Most lower abdominal pain resolves on its own or with straightforward treatment, but certain patterns warrant a trip to the emergency room:
- Pain so severe it interrupts your ability to function
- Vomiting you can’t control, especially if you can’t keep liquids down
- Complete inability to have a bowel movement combined with severe pain and bloating
- Pain that started near the belly button and moved to the lower right, worsening over hours
- Fever with localized tenderness, particularly if the area is rigid or extremely sensitive to touch
- Pain that resembles a previous episode (like a past bowel obstruction or kidney stone) but feels worse or different this time
If you’ve had prior abdominal surgery, adhesions (internal scar tissue) can cause bowel obstructions that produce sudden pain, vomiting, and inability to pass gas or stool. That history is worth mentioning when you seek care, because it changes what doctors look for.