bleeding after sex??

Okay!! So, I've had a steady boyfriend for about 8 months. He is umm well-endowed, or however you wanna say it, but I haven't had any issues until recently. I'm not sure if it has anything to do with that. Anyways, recently everytime we have sex, when he pulls out, there is a little bit of blood on the condom, on the right side. It's a tiny bit and doesn't continue, it's mostly just brown residue, only once it was red. I also have felt a little bit of pain on the side the blood is coming from, like when I sneeze or poop (aka strain my muscles) and a few weeks ago, the same spot hurt during sex but there was no blood. I went to the obgyn for birth control and asked him about it and he looked and felt and said it was nothing. ???