My hands and wrists were really bad with PMR before starting on prednisolone. Couldn't open doors, lift the kettle, couldn't push blankets aside to get out of bed. You're definitely not alone with that symptom.

Do you have 1mg or 2mg tablets to make smaller reductions? Making 5mg or even 2.5mg reductions once you're down to 15mg is way too much for most people and would bring on a return of pain. Slowly slowly does it from now on. Can you ask your doctor for smaller dose tablets?