Hi! thanks for sharing your health concerns with HCM! Well, I ve gone through the details of your problem and can realize that the problem is intermittent, right-sided and aggravated by masturbation but the testis itself is not tender! Therefore, if I were your treating physician , I would just point at your right spermatic cord and the right epididymis! Yes, you need to take rest after masturbation in supine position, avoid strenuous exercises, wear a tight underwear and press some ice-pack/cold compress in the area as this is nothing but due to pressure/mild partial torsion to the cord/epididymis! Therefore, you have to do a USG with doppler if the problem is not responding to me advises and also do not forget to revert back to us! wishing you good health!