Is it possible for an STD to form without actually having sex with someone who has one? My girlfriend and I had sex earlier (without a condom, she's on the pill and I didn't have one. I know, I know. Don't lecture me.) and now "I'm" doing weird things. The head is really dry and itchy and the left side of the shaft is red and kind of sore. When we were, uh, engaging... we experienced something that we don't usually experience. It felt like I was hitting a wall. Everything went smooth until about 5 inches in, then just a brick wall, and it hurt. A lot. Can anyone help me? I'm definitely going to a doctor tomorrow, I just want to know if anyone has experienced anything similar, or just if anyone knows what the hell is going on.