While pain medication can reduce the discomfort you are having, it will not eliminate the cause. I suggest that you get a second opinion from a doctor with lots of experience in treating J pouch problems. Unfortunately, doctors like your PCP often recommend an ileostomy without considering the quality of life that their patient desires. The two alternatives to a conventional ileostomy are the K pouch and the similar BCIR, both of which do not require having an external bag and both have high success rates. I would definitely stay away from “street” drugs due to lack of quality control.
I agree on determining the cause but I do not feel I should have to go thru a life changing event that getting an ileostomy would bring on just to manage pain. As I said in previous reply, do we tell people that have degenerative lumbar in the spine to have it removed and be wheel chair confined for the rest of their lives. Do senior citizens that have arthritis in their hands have them chopped off? Of course not! So why should this be any different?