Hi, Thanks for posting in HCM. I understand your concern. Experiencing pain in the testicles following act of masturbation could be due to spasm of pelvic muscles. Kindly take analgesic with muscle relaxant medications like Diclofenac, Paracetamol with Chloroxazone after food twice a day. Drink good quantity of fluids. Gradually, your symptoms should subside. Also decrease the frequency of masturbation, if you are habituated to do it more frequently. Masturbation is a healthy sexual behaviour and normal physiological phenomenon. Like other behaviours, over doing it, can lead to both psychological and physiological imbalances. Over-masturbation could lead to sexual under performance by way of premature ejaculation, as well as other sexual problems. Hope the information provided would be helpful. All the best.