Your symptoms sound like you have
proctitisProctitis
Proctitis - streptococcal (
rectalAnorectal fistulas
Colon cancer
Colorectal polyps
Digital rectal exam
Hemorrhoids
Imperforate anus
Imperforate anus repair
Inflatable artificial sphincter
Proctitis
Rectal biopsy
Rectal cancer, x-ray inflammation), which is common in gay men and most commonly is due to gonorrhea, chlamydia, or herpes. But you say nothing about the nature of your sexual exposure; sexually acquired proctitis requires being the receptive partner (“bottom”) in anal sex, although sometimes it occurs in women without anal intercourse. If you did not have receptive anal sex, then your symptoms probably aren’t due to the sexual exposure you describe. Non-sexually acquired proctitis can occasionally accompany other gastrointestinal infections, or can be a sign of inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease.
In either case, you should see a health care provider, preferably one who understands proctitis and how to diagnose it. Your local health department STD clinic is a good bet, especially if you were a bottom in that exposure. Otherwise, a primary care provider or a gastroenterologist would be fine.
PS: After composing the above off-line, I saw your follow-up comment. Unless there was trauma to your anal area during sex--e.g., vigorous manual stimulation--I don't see how your symptoms can be related to the sexual exposure you describe.
Good luck-- HHH, MD