I Am 28 .my Testicles Seem To Become Small ..and

I am 28 .my testicles seem to become small ..and my right testicle is little smaller than left..I masturbate regularly 3 times .from 16 and suddenly I feel some change near my testicles ...I checked for any malignancy but nothing is there...but slight pain which lasts only seconds above my penis..but I have no symtoms ..I look healthy...should I stop matturbating