well, could be epidydimitis, could be from lifting harder causing irritation in a disc in your back causing your mind to tell you there's pain in your testicle.
weird thing is, i had pain all year in my testicle before i ever ran a cycle in my life. went on cycle, no pain whatsoever. weird eh. but i've read somewheres that AS can cause the epidydimitis. look it up and maybe get some antibiotics. you can also get it from exercising, hence, go get it checked out, piss can leak down into your sperm sacks causing it, anal sex. good luck bro.
caffiene also negatively affects the prostate which if inflamed can cause testicular pain. just some tips because nobody really knows what caused mine, seen 2 urologists, 2 doctors, 2 ER visits, 2 ultrasounds and 1 catscan. so i've learned alot in the time being about testicle pain and when it comes to it, docs don't know shit about why. but antibiotics could clear it up possibly. good luck man, it sucks
and i did hcg which shrunk my nuts up like no tomoorrow and had no pain. never heard of pain from shrinking.