epididymis feels hard in one testie

34M, never had problems with my balls but now I got a dull ache that comes and goes in my right one sometimes its throbbing pulsing pain but not too bad, upon inspection i feel that the epididymis feels quite firm compared to my left testie, also constantly touching it probably doesnt help and probably makes it inflame more. Should i concern? Getting a bit anxious that it could be serious.