Sounds like arthritis, morning pain and stiffness that eases with use.
I have it in my thumbs, which is very common. Using hammer drills, screwdrivers or a lot of heavy work on the car with spanners/socket wrenches tends to upset it. It also tends to be seasonal (worse in winter) and flare up after I get flu or a bad cold. Ibuprofen helps, so does using, although getting back into playing has brought it on. Usually just a constant dull pain I can generally ignore but occasional I do something that causes a twinge which can vary from unpleasant to oooooowwww! Sometimes I can open the tightest of jar with my hands, sometimes I can barely grip them.
I've ordered some 'indian frankincense' after looking on the versusarthritis website as it seems to be one of the few complementary treatments where all the climnical trials have shown a positive effect. Also taking chondoitin and glucosamine.
The good news is exercise is very good for arthritis and one of the best treatments I have found is playing my acoustic guitar fingerstyle.