What Causes A Hard Bump On The Shaft Of The Penis?

I am a 49 year old male. I am overweight. A couple of weeks ago I was doing some lifting and afterwards I noticed a large hard bump on the shaft of my penis by the base. I should also mention that it was after a weekend of vigorous sex with my girlfriend.

I went to the doctor who said that he hadn't seen anything like this before...thought maybe it was a hernia or a fluid-filled cyst. He put me on antibiotics and gave me hydrocortisone cream.

Since then the lump has gotten progressively larger to the point now that it is interferring with urinating. I am going to the doctors tomorrow

to have it drained but the doctor still hasn't given me any answers as to what it is or what it is from. Can you help?

Thanks,

Dave