The solid, painful bump on my wrist bone

So, here’s a photo of the solid, painful bump on my wrist bone.  No, I’ve never broken it…  It doesn’t hurt all the time.  It only hurts if I press on it, and it is quite solid, like bone, or when I bend my wrist in certain positions, such as this one for the photo to demonstrate it’s out-of-whack-ness.  I also can’t bend my wrist backward very far – not nearly far enough to do a push-up.  This started out small and I had noticed it about six months ago.  The reason I’m noticing it now is because it’s getting arthritic-feeling, whatever it is, and brings stiffness and soreness to my left wrist.  It also limits my mobility in that wrist, which isn’t a good sign.  I see my primary care doctor on Monday.  This one’s on the table for examination and discussion, for sure!  I need to be able to climb!!!