Burning sensation in my urethra?

Ok, well I'm 17 yrs. old and since this morning I'm felling a burning/discomfort sensation in my urethra like the tip of my . Although it doesn't burn when I pee. I last had about two weeks ago but it was all protected from oral to . Before that I hadn't had for about two months. So what do you guys think this is?? I'M making an appointment to see a doctor tommorrow to see whats going on (I hope its not an STD or anything serious). Could it be from tight pants that i wore that maybe irritated my urethtra? Thanks guys.