Epididymitis is often unilateral
Is this still an issue? Antibiotics and "supportive undergarments" can often fix this
Antibiotics only help if it's bacterial. Congestive epididymitus isn't and I don't believe "althetic sipp otters" help with that type. But hopefully it's gone or bacterial and easily treatable.
I imagine the OP would know if he has a vasectomy, though.