It could be an std, but the changes in urination and the pain with ejaculation suggests prostate. STDs don't typically change anything about your urine stream.
I'd say its not terribly likely that you inflamed the end of your urethra during sexual contact, but its possible.
Aj
Since I don't have discharge, we're thinking it isn't an STD? Is there a chance I inflamed the end of the urethra during oral or vaginal intercourse?
This sounds like it could be prostatitis, and you should see your doctor promptly.
Aj
So, I guess I never asked a question. Is it possible that the end of my urethra is just inflamed front fast or rougher sex? And that I don't have gonorrhea.