I am a 52 year old and I recently noticed that when I have an erection I have a soft area about half way down the shaft and about 15mm long. I also have a small lump in the same area when my penis is flacid. From the information I gained from google it seams this lump, and a more general hardening along the length is in the main vein that runs along the top of the penis.
HelloThanks for query. Based on what you have described as soft mass on shaft of the penis is a dilated or prominent tributary of dorsal vein of penis. It is nothing to be worried about. It is not going to hurt you or bother your sexual activities. Chat Doctor.