And there you have it.
Benign bone tumor. Likely to go away on its own. Plan is to keep managing the pain with aspirin for awhile yet (at least until I get some of this weight off and am used to walking again), and if it doesn't take care of itself in another twelvemonth or so, I can go back for the radio-frequency ablation treatment. It's not terribly invasive, but it does involve general anesthesia.