Last year in December i got a new girlfriend and had sex once unprotected also had sex twice with a condom and tryed anal and had oral a few times both unprotected the last time we had sex was in march of 2015. And i was worried about pregnancy so i didn't worry about STDS at the time and now a week ago l had a little soreness in my groin/ left testicle. So i did some research and now im worried it could be an STD. Its not major its just a dull sorta pain and not constant it comes and goes mostly when im not doing anything or start having time to think about it. am i just making my self believe something is wrong or should i be concerned and get it checked out?