although they don t hurt I have found 4 mole/freckle type markings appear on the shaft of my penis which were not there until recently, I noticed that in the area where these are there is a pea sized lump under the skin and when flaccid can be felt with no pain however when erect it appears concave as if the muscle is affected by the lump, any ideas as to what this might be or if it s anything to worry about?