I have tense testicles to explain better instrad of my scrotum being saggy it is firm is this bad?

Normal: I assume you are referring to the scrotal skin only, not the testicles. If the testicles have become firm see a doc. Otherwise completely normal.

Probable hydrocele: A tense enlarged scrotum is usually due to a hydrocele which is a fluid filled sac around the testicle. You should have it checked out with a scrotal ultrasound because testis tumors, which are not too common, are often surrounded by hydrocele fluid. However, most hydroceles are benign and easily treated by a simple outpatient operation.