What Causes Recurring Pain In Testicles?

I woke up in the middle of the night because my testicle started to hurt. When I got up this morning I was okay, but later this afternoon my testicle started hurting really bad. There's no swelling or any sign of unusualness. It hurts really bad when it's touch. Do you know what's wrong? Did I cut off blood circulation which causes it to hurt when touched?