Anal pain is caused by the following reasons: 1. perianorectal infection, especially high abscesses above the anal raphe, caused by occupying swelling at the bottom of the pelvic cavity and stimulating the surrounding nerve tissue. 2. masses at the bottom of the pelvic cavity and pre-sacral tumors, cysts and pelvic floor hernias in the posterior rectal space. 3. inflammatory diseases of the rectum and lower sigmoid colon, such as ulcerative colitis, caused by inflammation of the intestinal mucosa and edema stimulation of the intestinal wall. 4. 4, tumors in the rectum, the tumor in the intestinal cavity grows to obstruction and infiltrates into the perirectal tissue caused by. 5, pelvic floor relaxation, spasm and degenerative changes caused by pelvic floor organ prolapse, pelvic floor drop, and part of the exit obstruction type constipation patients often have the symptoms of drop.