I have a lump in my scrotum but its not on my testicle what could it be?

Many things.: If this is in the skin it is often a sebaceous cyst. If it is inside the scrotum but outside and free from the testicle itself it can be an enlargement of the cables (nerves, spermatic cord, and blood vessels) that connect the testicle back to the abdomen. (cystocele, varicocele, spermatocele). It could also be a hernia.

LUMP: The epididymis is a collection of tubes that eventually form into and connect to the vas deferens. These tube can and often form cysts called spermatoceles or epididymal head cysts. They are usueally on the back of the testis or the top and are very round and non-tender. It should be checked by a urologist.