The right side of the stomach pain when running may be caused by abdominal wall muscle contusion, intestinal spasm, appendicitis, kidney stone and so on. 1. Abdominal wall muscle contusion: running due to muscle tissue movement, may lead to muscle contusion, which in turn causes the right side of the stomach pain. 2. Intestinal spasm: running due to the body’s movement will lead to intestinal tubes as well as the body intestinal peristalsis accelerated, may cause intestinal spasm, which in turn leads to the right side of the abdominal pain. 3. Appendicitis: chronic appendicitis usually less painful, running with the body movement will cause intestinal and appendiceal position changes, which leads to obvious right side of the stomach pain. 4. Kidney stones: running may cause stones to fall out of the blockage, causing the right side of the abdominal pain. There may be other pathological factors that lead to the right side of the stomach pain when running, if the pain continues to be unrelieved, it is recommended to go to the hospital as soon as possible to seek medical treatment.