I have a small bump on the top of the shaft of my penis. It sometimes becomes irritated and red, but normally it is just a tiny, skin colored bump. It is not real hard, but when I have an erection it is harder. It has been there for over a year now, but I have no had any type of sex for three years, so I doubt it is an STD. It isn't particularly painful, but at times it bothers me, probably just because I know it's not normal.