Itching sensation inside penis

I seem to have a nagging/intermittent itching type sensation inside my penis.  There is no discharge.. it Does Not burn when I pee either.  But its just something that doesnt feel quite right.  I dont know if this is related, but i seem to have a pretty strong post-nasal drip in the back of my throat.  I was having unprotected sex with a girl I had been seeing, but its been an exclusive relationship.  Any ideas as to what this could be? What course of action I should take.. or has anyone had similiar symptoms: No Discharge, No Burning, but itching-stype sensation and had it diagnosed?

[joggen]

Your symptoms do not sound like a STD. See a doctor for proper diagnosis.