My hands have been cramping bad and it's hard to close and open them. This has been going on for a few years now. I think its Arthritis and my wife thinks its because I'm always on my phone looking at the model runs lol. I'm going with the Arthritis idea.
Are you feeling stiffness in one or more of your knuckles? If so, is this affecting only one or a few fingers of each hand or is it all of them?