I am a 20 year old man, and for the last year or so every so often when I masturbate about 5 minutes after ejaculation I need to pass urine and after that I get a stinging sensation in the shaft of my penis.
This doesn't happen everytime, but I think it has been getting more regular recently. I can't seem to notice any pattern to it, so I don't know what its caused by. I have a girlfriend and after sex I have never had the same problem.
The pain lasts about 10-15 minutes. It isn't agony but uncomfortable.
What kind of thing could this be? I'm a little embarrassed to go to the GP until I have some idea what it could be.