What to do about severe pain in my wrist from bones shiftingneed surgery soon?

Not necessarily: If there is no damage to the bones, but they are shifting due to stretched/damaged wrist ligaments, a more conservative treatment would be prolotherapy - an injection therapy used to strengthen & tighten ligaments. It's a lot better than wrist fusion, allowing normal function of the wrist. If it fails, you can always still get surgery, later.