Hi, ive searched around on the net but couldnt find anything particularly useful, so i decided to post my problem here. Ive been masturbating for the past year, without any problems( once, daily). a month back, i started to feel a slight pain in my anus, it was negligible, but i became worried about my prostate and stopped masturbating for 4 days or so. the pain vanished, and i continued to masturbate, but only around 5 times a week. 3 days back, i had this pain in my left testicle. i had experienced this before once or twice in the previous year, but it went away in a couple of hours. this time the pain was persistent throughout the day, but nothing unbearable. so i ignored it, and the next day my left thigh also began hurting, but the pain in testicle(left one) reduced. today, the pain is almost gone from my left testicle, but it is on my right side of the groin now.( slight pain in right testicle, too.) and a little pain in my prostate(atleast i think its my prostate.) but it lasted only a few minutes. i also have slight pain( pressure-like) in my lower left abdomen. 
so, is this epydidymitis, or something else? should i go see the doctor? and will he able to tell if i masturbate or not?

and yeah, im 13.
plz help out guyz..............................thanks.