This sounds like an STD, we answered your question
here and
here (although the answers here make me laugh)

.
It does sound as though you have an STD and should get it checked out by your doctor ASAP, before it develops into something very serious if indeed it is an STD.
Please make a doctor's appointment. This could be dangerous to your health and to the health of any partner you have.
Oh, yeah, don't be afraid to visit the doctor. Make sure it is a male doctor, he has a penis too, so he sees one all the time. Makes it much easier when you see a doc of the same sex.