What Causes Swelling And Pain In Testicles?

Hello i have been in and out of drug and alcohol treatments since i was 19. I had hodgekins lymphoma which i took chemo and radiation. Addiction has been a struggle for a long time. I relapsed again in march and i gues given up. I have high blood pressure thyroid disease and was taking metforman for high sugar. I must of gave up hope last march because i havvent sought help. I instead have been a daily user of meth smoking but since august injecting on a daily basis i havent left the house and use drugs smoke and drink daily in a suicidal manner. In about june i was smoking meth and my teticals swelled up and the pain was unreal. I never stoped it happened on and off since i notice that my spermatic cords ard hardened and testicles have hard quarter size knots on them. I have in know wy taken care of myself ignoring pleas from family and friends. In june i lost my insurance and try and fight the pain. Sometimes so severe i cant walk or sit. I researched and epididymitis was what i related with. I know it sounds insane that i do this to myself and to tell the truth i dont know why. I know i nead to see a dr. I need help getting back on track but dont seek it out. The only thing that relives the pain a little is masturbating. It hurts like hell to do but when i ejaculate the same place that hurt so bad feel insanely intense and the harder i hit it the better it feels untill i ejaculate then the pain creeps back in. What could this be?