Left testical HURTS!!!!!!?

hi. for the past year or so my left testicle has had sharp pain (about once a month). but just tonite i was laying in my bed trying to sleep when BAM! it hit again. only this time its horrible. i broke into tears it was so bad. when i tried to touch it it REALLY hurt. even if it touched my leg it hurt. my right one is fine just the LEFT!.im scared and dk wat to do. would like to know wat it is.. ps. im 16 plzzz help :( :( :( :(