Hand pain is often caused by arthritis. Women especially start in their 40s with pain in the thumb joint and the joint above the thumb.
See the link to https://arthritis.ca/
Another cause for hand pain is carpal tunnel syndrome. if you have symptoms – you will need blood tests and testing of your nerves – EMG testing. Until you get this done, use a carpal tunnel syndrome splint at night and do these exercises.
Trigger fingers can be annoying and painful