There are many reasons for running pain in the right lower abdomen, which is related to incorrect warm-up, rectus abdominis muscle spasm, intestinal spasm, kidney stone, appendicitis or ovarian cysts in women. 1. Inadequate warm-up: running immediately after inadequate warm-up will increase the intensity of the exercise because the internal organs have not yet adapted to it, affecting the venous blood return, causing liver and spleen bruising and swelling, and resulting in tugging pain. 2. Rectus abdominis muscle spasm: due to the loss of large amount of water and salt, metabolic imbalance in the body and other factors, it can cause spasmodic pain of rectus abdominis muscle. 3. Intestinal spasm: when running inhaled a large amount of cold air, coupled with the stimulation of running movement is more intense, it will cause sudden intestinal spasm caused by abdominal pain. 4. Kidney stones: young and middle-aged men who have lower right abdominal pain while running should consider whether it is caused by kidney stones. Normally, most of them have no obvious symptoms, but when running and other strenuous exercise, kidney stones fall into the ureter to cause ureteral urine obstruction, infection, etc., will cause abdominal cramps, nausea, abdominal distension and other symptoms. 5. Appendicitis: appendicitis is relatively common among young people and has an acute onset. Usually there is pain in the middle and upper abdomen first, then fixed right lower abdominal pain, and also accompanied by nausea, vomiting, fever and other symptoms. 6. Ovarian cysts: Women should consider whether running lower right abdominal pain is caused by ovarian cysts. Normally it may be painless, but when the cyst slowly grows larger, pressure, inflammation, or stimulation from strenuous exercise, it can trigger pain at the cyst. There may be other causes, so seek medical attention if you are experiencing discomfort.