I am 18. My left testicle seems to be more big than my right testicle. The left one seems to be "filled". By filled I mean as in more dense, heavy, and feels as if is a miniature brain or compressed intestine. The right testicle is completely different. It is about 2/3x smaller than my left testicle, and feels smooth (picture an egg yolk), and round. It feels as if there is no growth and it is stuck at a premature stage. Could this be normal? I highly doubt it, but I would like to know more before I go visit the doctor.