Hi, im 17 and i believe i am quite healthy. sometimes, after urininating, my testicles or somewhere between my testicles and my anus is aching. this ?

See below : The area between the testicles/scrotum is called the perineum and discomfort in this region in a male is commonly related to a non-bacterial, non-specific prostatitis: an inflammation or irritation of the prostate gland. Infection-related prostatitis also occurs, but less common. If persists or is associated with other urinary symptoms (poor stream, urgency, discharge, etc) recommend see urologist