Once upon a time I was a really good guitar player, then I got tendinitis due to typing and now I can't play guitar anymore because it fucking hurts...and this is ten years later. Don't take any chances with your hands, they are what separates us from monkeys - dexterity and opposable thumbs.
Do stretching exercises before and after typing. You can find these on the 'net. If that doesn't help, switch to using index fingers only and relax the rest of your hands. If that doesn't help...take a long break from typing and talk to a doctor. You may need some anti-inflammatory steroid injections.
REPEAT: DO NOT TAKE CHANCES WITH YOUR HANDS!