Tightness in your hands and fingers are common from repetitive texting and/or keyboard work. Just as you need to make a conscious effort to offset your sedentary job with exercise to stay at your healthiest, you also need to offset the effects on the muscles of your fingers and forearms from your repetitive typing. Below are some stretches to do just this
With your palm facing up stretch one finger at the time back down towards the floor. For your thumb make a fist and make the thumb facing up towards the ceiling then pull it back towards the elbow. You can toggle the thumb back in slightly different angles towards the right and left. Once you have gone through all the fingers; go back to combined stretching 2 or 3 different fingers at the time as this will target different muscle groups.
Work your way up to 60 sec and repeat 3 times per day for best result.