hi am 19 and iv been worried about my testicles as thay hurt every now and then, mostly when i sit down. my testicles seem to go red aswell wen it hurts sometimes. i visited the doc and he seemed to think it wasnt more than a sist i told him it hurts,and that thiers swellin in the veins in my testicles! i was wonderin if it was a std? should i be worried!?! why is the pain still going on?? its been like dis for a while now!