What Causes Penis Pain After Ejaculation?

my penis hurts after sex. After i ejaculate it hurts for a couple hours. The pain is inside the penis not the top of my penis. the pain is not that much painful where i want to cry. but its uncomfortable pain. This uncomfortable pain has been goin on for a couple years now. Do you have any idea why this pain is occurring. and do you know how i can make iit stop