Suggest Treatment For Lump On The Penile Shaft

Hi, I have a bee bee like pebble on the right underside shaft of my penis but I can not see it because it is under the skin of my scrotum. It is painless and gets maybe a little inflammated when erect. I have to feel it or else I would never know its there and I didn t think hair grew that far back on your penis going into the scrotum. What could it be and will it go away on its own???