Suggest Medication For Itchiness Around Penis After Taking Shower

Hello...i take bath every morning, but in the evening and in the morning (before taking shower) it really itches around my penis area and sometimes it really smells fishy....i am really worried about this problem...is this some kind of STD's?. The first time i had sex was, i guess 4yrs ago, however as far as I remember, this problem started even before this...can you please help me to understand this problem...