Why does my testicles hurt. they been hurting on and off for some years now. usually one side hurt or the pain will be in an area?

Here are some ...: One should consider the possibility of experiencing intermittent recurrent testicular torsion (twisting) with spontaneous de-torsion (untwisting) for a 17-man with the clinical scenario as described. Generally speaking, a Hx of highly variable onset, degree, duration, interval, resolution of recurrent testicular pain should alarm professional mind to think about such as described. ...

Testicular pain: Several conditions come to mind as a cause of testicular pain, the most worrisome of which is torsion whereby your testis twists on itself cutting off its blood supply. This is a surgical emergency. Less threatening causes include infection (but these don't tend to come & go w/o treatment), trauma, perhaps even inguinal hernia. Occasionally, someone will complain of blue balls. Go see family doc