Definition. Proctitis is an inflammation of the lining of the rectum. The rectum is a muscular tube that's connected to the end of your colon. Stool passes through the rectum on its way out of the body. Proctitis can cause rectal pain and the continuous sensation that you need to have a bowel movement.Proctitis symptoms can be short-lived, or they can become chronic. Proctitis is common in people who have inflammatory bowel diseases.tool passes through the rectum on its way out of the body. Proctitis can cause rectal pain and the continuous sensation that you need to have a bowel movement. Proctitis symptoms can be short-lived, or they can become chronic. Proctitis is common in people who have inflammatory bowel diseases.