What Causes Clear Penile Discharge?

Hi, may I answer yo Hi i am 15 years old. i have clear see through discharge coming from my penis every night or every other night. however i have no pains at all that other people that have STDs have e.g swollen ball sharp pains when urinating.i have no pian at all.i have also never had sex before in my life and the only person that has touched my penis is me so they is no way anyone has given me this.it only happens at night before i goto bed. i had a wank nerly every night . dose it sound like i have a STD and what type?