Had sex about 4 weeks ago. I had one bump 2 days after and it went away after a week. when i popped it puss and blood came out then swelling went down. Now today (4/18/13) i woke up and i had burning sensation in my penis when i pee. Is it a UTI or is it chalmydia or gonnoreah or any other STD?!?! As the day progressed the burning sensation would happen only in the beginning when i pee then i can pee normally, but after i finihed peeing if my penis touched my underwear the tip of my penis hurts alot! for about 2 minutes after im done PLEASE HELP!!!