Pain at the bottom of your stomach, the area between your belly button and your pubic bone, can come from your intestines, bladder, appendix, or reproductive organs. The cause depends on exactly where the pain is, how it started, and what other symptoms you’re experiencing. Most cases trace back to something manageable like a urinary tract infection, constipation, or muscle strain, but certain patterns of pain signal something that needs prompt medical attention.
What Lives in Your Lower Abdomen
The lower abdomen is a crowded space. Your small intestine, colon, appendix, bladder, and ureters all sit in this region. If you have a uterus and ovaries, those are here too. Pain can also be “referred” from somewhere else: kidney problems originating in your back can wrap around to the front, and testicular issues can register as abdominal pain.
Because so many organs overlap in this area, the location of your pain is one of the most useful clues. Pain on the lower right side points to different causes than pain on the lower left, and pain centered low behind your pubic bone suggests the bladder or uterus rather than the intestines.
Lower Right Side Pain
The most important cause to rule out on the right side is appendicitis. It typically starts as a vague ache around your belly button, then migrates to the lower right within 12 to 24 hours. The pain gets sharper over time and worsens when you cough, walk, or make any jarring movement. If you press on the area and releasing the pressure hurts more than pressing down, that’s a classic warning sign.
Not all right-sided pain is appendicitis. A pulled muscle, a flare of irritable bowel syndrome, or an ovarian cyst on the right side can all land in the same spot. The key difference is the progression: appendicitis gets steadily worse rather than coming and going, and it’s usually accompanied by nausea, loss of appetite, and sometimes a low-grade fever.
Lower Left Side Pain
Pain on the lower left is the hallmark of diverticulitis, a condition where small pouches in the colon wall become inflamed or infected. These pouches, called diverticula, form most often in the lower left portion of the colon and are increasingly common after age 40. When one becomes inflamed, the pain is usually sudden and intense, though it can also start mild and build over hours or days.
Diverticulitis often comes with fever, nausea, and a noticeable change in your bowel habits, either sudden constipation or diarrhea. The area feels tender when you press on it. Mild cases can be treated at home with rest and a temporary change in diet, but more severe episodes involving infection or abscess formation need medical treatment. A CT scan is the standard way to confirm diverticulitis and check how extensive it is, with a sensitivity above 95% for this condition.
Pain Centered Low, Behind the Pubic Bone
A dull pressure or ache sitting right behind your pubic bone often points to the bladder. Bladder infections (cystitis) cause a persistent urge to urinate, frequent trips to the bathroom where you pass only small amounts, and a feeling of pressure in the lowest part of your abdomen. The pain tends to feel more like a constant heaviness than a sharp stab, and it gets worse as your bladder fills.
Bladder infections are far more common in women than men due to a shorter urethra. If you’re also noticing burning with urination, cloudy urine, or urine that smells unusually strong, a UTI is the most likely explanation. A simple urine test confirms it.
Reproductive Organ Causes
For people with a uterus, lower abdominal pain has an entire additional category of possible causes. The timing relative to your menstrual cycle is one of the best diagnostic clues.
Endometriosis causes pelvic pain that goes beyond normal menstrual cramping. It can show up during your period, between periods, during sex, or with bowel movements and urination. Lower back pain and lower abdominal pain are both common. Endometriosis sometimes produces cysts on the ovaries called endometriomas, which can cause a more localized, one-sided ache.
Ovarian cysts that haven’t ruptured often cause a dull, intermittent pain on one side. A ruptured cyst brings sudden, sharp pain that can be severe but typically improves over hours. Pelvic inflammatory disease, an infection of the reproductive organs usually caused by sexually transmitted bacteria, produces lower abdominal pain along with unusual discharge, fever, and pain during sex.
If there’s any chance you could be pregnant and you’re experiencing one-sided lower abdominal pain, ectopic pregnancy needs to be considered. This happens when a fertilized egg implants outside the uterus, most often in a fallopian tube. Risk is higher if you’ve had a previous ectopic pregnancy, a history of pelvic infections, or you smoke. A pelvic ultrasound and a pregnancy blood test are the first steps for any reproductive-age person with unexplained lower abdominal pain.
Muscle and Hernia Pain
Not all lower abdominal pain comes from internal organs. An inguinal hernia, where tissue pushes through a weak spot in the abdominal wall near the groin, can cause discomfort, heaviness, or a burning sensation in the lower abdomen. You might notice a visible bulge, especially when standing or straining. The pain typically gets worse when you lift, cough, or stand for long periods and improves when you lie down.
A simple muscle strain from exercise, heavy lifting, or even prolonged coughing can also mimic organ pain. The difference is usually that muscle pain is reproducible: you can find a specific movement or position that triggers it, and pressing directly on the abdominal wall recreates the sensation.
Digestive Causes That Come and Go
The most common and least alarming causes of lower abdominal pain are digestive. Constipation builds pressure in the colon that registers as cramping or a dull ache, especially on the left side. Gas trapped in the lower intestines can cause surprisingly sharp, localized pain that shifts position and eventually passes. Irritable bowel syndrome produces recurring cramping tied to bowel movements, often relieved (at least temporarily) after passing stool.
If your pain follows a pattern tied to eating, bowel movements, or specific foods, a digestive cause is the most likely explanation. These conditions are uncomfortable but not dangerous, and they tend to come and go rather than steadily worsen.
When Lower Abdominal Pain Is an Emergency
Certain combinations of symptoms indicate something that needs immediate evaluation. Sudden, severe pain that comes on within minutes and doesn’t let up is the primary red flag. Other warning signs include a rigid or visibly swollen abdomen, pain that gets significantly worse when the area is lightly touched or bumped, and signs of shock like a rapid heart rate, sweating, lightheadedness, or confusion.
Fever above 101°F (38.3°C) combined with worsening abdominal pain suggests an infection or inflammation that may need urgent treatment. Vomiting that won’t stop, inability to pass gas or stool, or blood in your stool or urine also warrant a prompt visit.
How Doctors Figure Out the Cause
The diagnostic process starts with where your pain is, how it behaves, and what else is going on. For right or left lower quadrant pain, a CT scan of the abdomen and pelvis is the recommended first imaging test. It can identify appendicitis, diverticulitis, bowel obstructions, and many other causes in a single scan.
For reproductive-age women, the workup often starts differently. A pregnancy test is typically done first, both to check for ectopic pregnancy and to avoid exposing a potential pregnancy to radiation from a CT scan. If a gynecologic cause is suspected, a pelvic ultrasound (transvaginal or transabdominal) is the preferred imaging study. It’s the go-to test for ectopic pregnancy, ovarian cysts, and ovarian torsion.
Many cases of lower abdominal pain, particularly those caused by gas, constipation, mild infections, or muscle strain, resolve on their own or with simple treatment and never require imaging at all. The decision to scan depends on how severe your symptoms are, how long they’ve lasted, and whether the pattern suggests something that needs to be caught early.