Itching on scrotum, no rash for three months since a sexual encounter. also accompanied by muscle/joint aches. std tests negative. what could this be?

Itching on Scrotum: Itching in the scrotum for the past 3 months since sexual encounter and all STD negative. You could have pubic lice even though it is sexually transmitted by having a sexual encounter with an infected person the STD test are negative because this is a lice the feeds on human blood. Treatment is like with head lice including genital area and anal area.

Please see a Urologist Doctor who is an expert in male reproductive organs and will give you a thorough evaluation and recommend treatment.