What could be causing my severe rectal pain and bleeding?

Anal Fissure common. From this limited detail, i suspect anal fissure. This is the most common cause for this combination of problems, however it is worthwhile to see your colorectal surgeon to make sure it isn't something worse. Start a high fiber and water diet. Use warm water baths. Surgery is curative if conservative measures fail.

Related Questions

What is causing my severe rectal pain and bleeding drops?

Prob. anal fissure. Pain during and after defecation is the landmark of anal fissure while bleeding is usually none or minimal. Read more...
Fissure. These are classic signs of an anal fissure, a tear in the lining of the anal canal. Sit in a tub of warm/hot water for 5 minutes three times a day, add fiber to your diet, use a stool softener and see your doc about some pain creams. Read more...

Is it possible for endometiosis to cause severe rectal pain?

Possible but unlikel. Endometriosis can implant on the outside of the rectal wall but very unlikely that it would lead to severe rectal pain, more likely causes would be things such as an anal fissure...See a colon and rectal surgeon if it persists. Read more...
Not usually. This could be a sign of something more serious and should be worked up by a colon and rectal surgeon or gynecologist. Read more...

Diversion colitis: can it cause severe rectal pain and pain with sitting due to inflammation of area and nerves?

It can. Diversion colitis, or symptoms in the remaining rectal stump, can be variable from none, to severe rectal pain, bleeding, fistula and infection. Diagnosis and treatment will benefit you. Hopefully you will become a candidate to get your bowel reconnected. Be well. Read more...