I recently went to the doctor and was told I had a Hydrocele on the left side of my testes. I visited a Urologist and had an ultrasound and they said other than the hydrocele everything was fine.

But I noticed when I masturbate I feel a hard "be-be" sized lump on the bottom part of my left testicle. It goes away when I don't masturbate.

Should I worry about this? Do you think the docs missed anything?