I've got a weirdly specific problem--

Last spring developed a bruisey lump on my upper forearm--right where I rest on the pads when I'm in the aero position. I don't even notice if I ride for an hour or so, but if I do a long ride or a high volume week, it gets painful and forces me to adjust my position a bit. (Rotating the forearm off the lump or moving sliding it back or forward a bit.)

I've had some weeks at a time of resting it. Either low mileage, or riding my road bike, or just not riding at all. But it seems like it's not going away.

Has anybody experienced anything similar? Aside from not riding aero, is there a way to treat this?