Anorectal problems involve the rectum (the last part of the colon) and the anus (the opening where waste exits the body). A hemorrhoid is a swollen vein in the anal canal. Internal hemorrhoids occur inside the anal canal while external hemorrhoids occur at the opening. They are usually not dangerous, but can be painful. Other anorectal diseases include anal fissure, rectal prolapse, anal warts, proctitis and levator ani syndrome. Rectal and anal problems can cause fecal incontinence, anus pain and difficulty moving your bowels (dyschezia).