Pain in the lower right side of your stomach most commonly points to a problem with the appendix, but several other organs and structures sit in that area and can be the source. The appendix, the end of the large intestine (cecum), the last stretch of the small intestine, the right ureter, and, in women, the right ovary and fallopian tube all live in this region. What’s causing your pain depends on how it started, how it feels, and what other symptoms came with it.
Appendicitis: The Most Urgent Possibility
Appendicitis is the first thing doctors rule out when someone shows up with lower right abdominal pain, and for good reason. The lifetime risk is roughly 8.6% for men and 6.7% for women in the United States, making it one of the most common surgical emergencies. Most people show up at the hospital within 24 hours of their first symptom.
The pain follows a recognizable pattern. It usually starts as a vague ache around the belly button, then over the course of several hours migrates down and to the right, settling into a sharper, more focused pain. This shift happens because the inflammation initially irritates deep nerve fibers that don’t localize well, but as the surrounding tissue becomes inflamed, the pain sharpens to its true location.
Other signs that point to appendicitis include nausea, vomiting, loss of appetite, and a low-grade fever. One telltale sign: the pain feels worse when you press on the area and then release. This is called rebound tenderness, and it’s a strong indicator of peritoneal irritation. If your pain is getting steadily worse, especially with fever or nausea, treat it as an emergency. A burst appendix can cause a life-threatening infection.
Kidney Stones and Urinary Tract Problems
A stone moving through the right ureter, the tube connecting your kidney to your bladder, can send pain radiating into the lower right abdomen. The pain typically starts in the back or flank and travels downward and forward into the abdomen, pelvis, and sometimes the groin. It tends to come in intense waves rather than staying constant, and people with kidney stones are often visibly restless, unable to find a comfortable position.
The key difference from appendicitis is the urinary symptoms. Blood in the urine is a hallmark sign, and you may also notice burning during urination, increased urgency, or cloudy urine. If the stone is accompanied by an infection, you’ll likely develop fever and chills as well.
Gynecological Causes in Women
For women, the right ovary and fallopian tube sit directly in this area, which means several reproductive conditions can mimic or overlap with other causes of lower right pain.
Ovarian cysts are common and often painless, but when one ruptures, it can cause sudden, sharp pain on one side. In some cases, a ruptured cyst bleeds enough internally to affect blood pressure and heart rate. Ovarian torsion, where the ovary twists on its blood supply, is three times more common on the right side than the left. It causes severe pain that comes on quickly and is a surgical emergency because the ovary can lose blood flow permanently.
An ectopic pregnancy, where a fertilized egg implants in the fallopian tube instead of the uterus, also causes lower abdominal pain, usually alongside a missed period and sometimes vaginal bleeding. This is a dangerous condition that requires immediate treatment. Pelvic inflammatory disease, an infection of the reproductive organs typically caused by sexually transmitted bacteria, can produce lower abdominal pain along with unusual discharge and fever. Endometriosis and ovulation pain (sometimes called “mittelschmerz”) are less urgent but can also cause recurring pain on the right side.
Inflammatory Bowel Disease and Chronic Causes
If your lower right pain keeps coming back or has been lingering for weeks, Crohn’s disease is worth considering. Crohn’s most commonly affects the terminal ileum, the very last section of the small intestine, which sits right in the lower right abdomen. The inflammation goes deep into the intestinal wall and causes thickening that can eventually lead to narrowing and blockages.
People with Crohn’s-related ileitis typically have recurring bouts of right-sided pain along with diarrhea, sometimes bloody, fatigue, and unintended weight loss. The pattern of symptoms waxing and waning over months is what distinguishes it from acute causes like appendicitis. Other infections and inflammatory conditions can also affect the terminal ileum and produce similar symptoms, though they tend to be shorter-lived and self-limiting.
Mesenteric Adenitis: The Appendicitis Mimic
In children and teenagers, swollen lymph nodes in the abdomen can cause pain that looks a lot like appendicitis. This condition, mesenteric adenitis, typically follows a recent cold or respiratory infection. The average age is younger (around 7 years) compared to appendicitis (around 10 years), and the pain tends to center more around the belly button rather than shifting clearly to the lower right.
Several features help distinguish it. Children with mesenteric adenitis are more likely to have fever and a recent history of respiratory symptoms. They’re less likely to have nausea, vomiting, or loss of appetite compared to those with appendicitis, and they don’t develop rebound tenderness. The condition resolves on its own as the underlying infection clears.
Hernias and Muscle-Related Pain
Not all lower right abdominal pain comes from an internal organ. An inguinal hernia, where tissue pushes through a weak spot in the abdominal wall near the groin, is a common cause, particularly in men. You may notice a visible bulge that becomes more prominent when you cough or strain, along with a dull ache that worsens with activity.
Muscle strains in the lower abdominal wall or irritation of the psoas muscle, a deep hip flexor that runs along the spine and through the pelvis, can also produce pain in this region. Psoas-related pain often worsens when you lift your knee toward your chest or when walking, and it can be confused with kidney stones, hernias, or hip problems. This type of pain usually has a clear connection to movement or physical activity rather than coming on spontaneously.
How Doctors Figure Out the Cause
When you go in with lower right abdominal pain, expect a physical exam that includes pressing on the area and checking for rebound tenderness, guarding, and specific signs that point toward appendicitis or other conditions. Blood work looks for elevated white blood cell counts and markers of inflammation or infection.
For imaging, the approach depends on your age and circumstances. Ultrasound is typically the first choice for children, young adults, and pregnant women because it doesn’t involve radiation and is widely available. CT scanning with contrast is the most accurate tool overall and is recommended by the American College of Radiology for adults with acute abdominal pain. Many emergency departments use a stepped approach: ultrasound first, and if the results are unclear, CT follows. For women of reproductive age, a pregnancy test is standard before any imaging, since ectopic pregnancy needs to be identified or excluded quickly.
What the Location and Timing Tell You
The character of your pain offers real clues. Sudden, severe pain that started minutes to hours ago and is getting worse suggests something acute like appendicitis, a ruptured ovarian cyst, or kidney stones. Pain that comes in waves and radiates toward your back or groin leans toward a kidney stone. Dull, crampy pain that’s been present on and off for days or weeks is more consistent with a bowel condition, menstrual-related cause, or hernia.
Pay attention to what else is happening. Fever with worsening pain raises concern for infection or appendicitis. Blood in your urine points toward the urinary tract. Changes in bowel habits alongside the pain suggest an intestinal cause. A missed period with lower right pain in a woman of reproductive age warrants urgent evaluation for ectopic pregnancy. Any lower right abdominal pain that is severe, rapidly worsening, or accompanied by fever, vomiting, or lightheadedness should be evaluated the same day.