Lump Found in Lower Right Side of Back

I have a friend that found a lump in the lower left side of his back. He refuses to go to the doctor to get it checked out. I took a look at it and it is visible. What I’m trying to say is that you can tell that it is there without feeling around for it. It’s not on his spine, it’s slightly to the left of it. When I touched it, it didn’t seem to move around too much. It feels pretty big though. I don’t know if he was just trying to act tough but when I pressed on it he said it doesn’t hurt.