I also have the wax thera tub - love it! The heat really soothes my hands. So do warmed oven mitts on my hands & rice bag on my neck (microwaved to warm) when I take a break or watch TV.
I have osteoarthritis in most joints & my back. Water aerobics keeps me moving and in less pain - I notice the difference if I miss a class. Stretching exercises & frequent breaks from sewing, cutting, etc also seem to help.
I try to avoid OTC drugs, but do like a natural product I found at local Health Food Store - Arnica rub & tablets.
Good luck.