Sorry, I'm afraid I can't give you a definite answer to this. Just my opinion, but I think whatever's causing the pain in your testicle could be contributing to this issue. But I think ultimately, you're going to need to see a Dr. who can examine you in person, determine if anything feels abnormal about the testicle, etc. You could start with your regular Dr. & then see a Urologist if it needs further follow-up. I know it's prbly gonna be a little embarrassing to discuss sexual matters w/ a Dr., but believe me, they know just about ALL guys at age 24 are going to have frequent sexual activity, including masturbation, which they regard as normal & healthy. They've heard just about everything, so there's very little chance they'd be embarrassed or judgmental about it. But you don't necessarily have to be specific about masturbation, just say "This is what happens whenever I'm involved in sexual activity" & leave it at that. This issue is of a sexual nature so there's no getting around it, so go ahead & make the appointment. I don't think you'll be able to get to the bottom of this without an actual Dr's exam, so just bite the bullet & do it - you'll be glad you did, I'm sure...