I've Just Noticed This Lump. It's Located Below My Ribs

I've just noticed this lump. It's located below my ribs on the right side of my back. I don't feel any pain, just a little tenderness from poking at it. It's about the size of a large egg. It doesn't move and it's hard. You can't see it.

I play sports so there's a chance that it could be from an injury. I've experienced bruised ribs..sprains.. strains..broken bones. It doesn't feel like any of that. I feel like I am over reacting. I've made a doctors appointment but I would love to cancel it. Any advice on what this dumb lump could be?