For about a year now I've had a bump on the underside of my penis.  Just under the head on the bottom of it.  It doesn't cause me any pain or discomfort and I can only tell it is there when erect.  At first I thought it might have been just a swollen gland and maybe it is.  When erect it seems to harden, but still causes no discomfort.  It's not large, but it's just present.  I haven't seen a doctor as it's caused me no real issues.  Just wondering if anyone had any insight or idea as to what it might be?