Burning & feeling to pee after sex

I've had sex with this person afew times now, but never have I burned after sex with him. The last time I had sex, was with someone else, and it did in fact burn, but I usually do burn after having sex with him.... I also have this OVERWHELMING feeling to pee, but I already have, and when I try to pee now, nothing comes out. Could this be an std? Its definitely not burning from friction!