What Could Be Causing Testicular Pain After Prolonged Masturbation Despite Normal Ultrasound Results?

Hello, Dr. Grzegorz Stanko, exactly, for about two years, after masturbating (if it lasts for more than an hour), I get pain in the right testicle area. This pain decreases a lot when lying down and gets better after a day or two. Through experience, I realized that the time of masturbation is very important, because as soon as you do long masturbation (2-3 hours), the pain starts after the completion of masturbation. Interestingly, even if ejaculation does not occur, there is pain after masturbation. Often the right testicle and rarely both testicles have pain. On the other hand, having sex with an ejaculating partner does not cause any pain at all because the sex lasts 20-30 minutes at most. The ultrasound results of my testicles were normal and I don t have swelling in the testicles. Thank you for your guidance.