I'm not sure if it is overuse, and allergy flare or just getting older, but I am dealing with this same issue. I have also had a number of surgeries on my hands and wrists, and finding it very hard to garden, watercolor, put in earrings...
To make matters worse, I cannot use most NSAID medications.
The things I am currently trying, and I cannot tell which are helping, are:
Daily hand flexibility exercises (from a hand therapist after one surgery)
Compression gloves
Hand/wrist braces for all physical activities - some are flexible neoprene, the ones for heavy activity are custom-made hard braces that I wear over compression gloves to protect my wrists and thumbs from further stress
Voltaren topical gel to relieve the pain. I massage it in 4 times a day. 1% is available over-the-counter. I have prescription strength (2% or 3%?)
My FAVORITE! A paraffin hand spa - I use it once or twice a day, putting mitts over the plastic bags to hold the heat in linger.

Seeing the rheumatologist next month to see if there is more I can do.