Penis head hurts

i've had a strange pain on the left side of the head of my penis for over a month now.
It started after I had sex with a girl with no condom ... Now for over month I've had a strange pain on the left side of the head of my penis. The head doesn't look damaged or any different from before. And I can touch the spot and not really feel much pain but there is a weird pain feeling i can deal with it but hate the feeling with i touch it.... i haven't stop Masterbating (masturbating) since because when im hard theres NO PAIN ! im thinking i need to let it rest ... so can someone please help me I dont want a STD or hiv

[codyshob]

it goes and comes back though the day