Burning sensation in right groin/thigh a few minutes after ejaculation. Sounds like prostatitis. Does herpes cause this or sound like a possible cause?

Many causes. Your pain could represent many things. Your vas deferens transports sperm from your testicles via your groin. You may have a hernia if there is a bulge present. Prostatitis is usually accompanied by fever, pelvic/rectal pain or pain when you urinate. A burning sensation on your thigh is usually a result of a nerve problem. I would recommend a physical exam to assess your problem.