I used to have that, and I almost thought it was the beginning signs of Carpal Tunnel Syndrome, but thankfully it wasn't. I was just on the computer too much at work and didn't have my keyboard/mouse properly adjusted. And I didn't take enough breaks to stretch my arms.
Some exercises you can do:
Extend and stretch both wrists and fingers acutely as if they are in a hand-stand position. Hold for a count of 5.
Straighten both wrists and relax fingers.
Make a tight fist with both hands.
Then bend both wrists down while keeping the fist. Hold for a count of 5.
Straighten both wrists and relax fingers, for a count of 5.
The exercise should be repeated 10 times.
Then let your arms hang loosely at the side and shake them for a few seconds.
Maybe this will help?