Im a virgin. why do i have a discharge from penis?

Physiologic: Virgin usually means never having had sexual intercourse with the opposite sex. That does not mean that you don't get sexually excited. With excitation, one will leak fluids from the pre-excitation glands like the cowper's glands and from the prostate and seminal vesicles. One can have mucous too. If you have a discharge that is other than clear, white and painless & no symptoms, get checked.

Seminal fluid: Responsible for "wet dreams". Production of seminal fluid is beyond your control. Release of seminal fluid, by masturbation, is under your control. The discharge is normal.