meh, I don't know exactly what's the problem. I've had pain in my testicles, where it only last for a second and was gone. I would bring this up to your doctor on your next check up, and if it does get worse or the pain gets more severe, directly go to your doctor.
do you give yourself a testicular cancer check, time to time, just to make sure there are no lumps? this routine should be performed often just to check yourself once or twice a month.

better safe than sorry, right? right!