You may have a tight tendon or two in your wrist to make it bind when you bend it. To get rid of that pain you have to free up the tendons in your wrist so they all become the same length again and here's how to do that:
With hand resting in front of you with the palm up, bend your wrist as far as you can.. Then press into the area behind the wrist, where they take your pulse, and hold a good amount of pressure on it. After 30 seconds slowly open your wrist up as far as you can, release the pressure but hold your wrist open for another 30 seconds.
for best results relax your body first by taking a deep breath and exhaling then remain this relaxed.
sounds like carpal tunnel syndrome