Hi I Feel A Little Lump On The Underside Of

Hi I feel a little lump on the underside of my penis few centimeters below the shaft.. It's not a blister it feels like there's something under the skin.. But there is a small nerve there..when I pull the skin down the lump goes away.. But when I masturbate it becomes harder u can't see but it feels hard and right side of my penis starts hurting I'm 20 and haven't had sex..