I Feel A Sharp Stinging Sensation Under My Right Testical.

I feel a sharp stinging sensation under my right testical. I'm 17 and this could happen every couple of weeks to maybe over a month. It almost feels like it is in the middle but I think it's a little to the right. Sometimes it feels like thumps, Minor stinging sensations and sometimes it can be pretty bad. This usually happens before or after I urinate and sometimes rarely after I masturbate it depends. What can this be?