Sitting down small stomach pain may be caused by colitis, may also be pelvic inflammatory disease, urinary tract infectious diseases. 1. Colitis: when sitting down, the intestinal tube of the colon is crowded into one piece, and the intestinal mucosa rubs and contacts each other, resulting in increased inflammation of the colon, aggravating congestion and ischemic changes in the colonic mucosa, and stimulation of the nerves on the surface of the colonic mucosa, which causes neuropathic pain. 2. Pelvic inflammatory disease: after the patient sits down, the uterus, ovaries and organs of the reproductive system are crowded together, easily congested and aggravated by pelvic gynecological inflammation, which leads to more pronounced pain in the stomach. 3. Infectious diseases of the urinary tract: sit down small stomach pain common infectious diseases of the urinary tract, especially in the bladder area, sit down urine retention in the bladder, drainage difficulties, bladder inflammation aggravated, the symptoms of red urine. There are other possibilities for sitting stomach pain, such as female pelvic tumors, etc. You should go to the hospital outpatient clinic in a timely manner to clarify the cause of the disease, and treat it under the guidance of a professional physician, and do not use your own medication, so as not to delay the condition.