Hello, What you are describing is most likely the consequence of too much blood remaining for a long period of time in your testicles, causing tension on the blood vessels and finally pain. The medical term for this is epididymal hypertension (more commonly known as blue balls ). Usually after an orgasm this can slowly improve, although in another cases the dull pain can remain for around a day, with some worsening with physical activity or movement of the area. In my experience, the first advice would be to masturbate less frequently and to finish the session with an orgasm, so that your genitals are decongested from the blood that was in the area. In case that the pain remains, it would be advisable to go with a Urologist.