What Is The Small Palpable Lump In My Scrotum?

Hi I have been looking for information about the so called 'third testical' I don't think I actually have a third testicle but similar?.. it is bellow my scrotum and is only half the size of a pea if not less.. it seems to be detatched for the most part and attached only by the outer flesh of the sack.. I have had is since I can remember.. is it anything to worry about?