It's always good to get things checked out. Most of the time, the doctor will do a quick exam and then ask for an ultrasound. It's rather painless and they'll literally do a complete exam of your whole sac. If you're lucky you'll get a cute technician who will squeeze goop on your balls and rub them around for 5-15 minutes taking pictures.

I personally have three cysts in my right testicle, two in the left, a granuloma in the left side veins, as well as significant varicoceles on the left. I've even had a 2.3cm x 2.1 cm x 1.8 cm cyst removed from the right testicle as it was painful.

Needless to say, I feel great knowing it wasn't cancer and so long as you have no pain, noone is going to cut anything off down there.