As computer use has increased both at work and home in recent years Repetitive Strain Injury (RSI) has become associated with keyboard use. To reduce your risk of developing RSI or other overuse injuries you should follow best practice in posture, technique, workstation set-up, and take regular breaks.
Listen to your body. If typing causes you pain, stop. If the pain persists, consult your doctor.
Sit with your back straight and your feet, either flat on the floor or on a foot rest. You should be arms length, 12-30 inches (25-75cm), from your computer monitor (VDU). Raise the monitor (VDU) so the your eyes are level with the top of the screen. Make sure the F and J keys of the keyboard are immediately opposite the middle of your body.
When typing, keep your elbows close to your body, wrists and forearms level. After striking each key return your fingers to their resting position over the home row.
It is desirable to avoid staying in one position for extended periods. Break up your day by alternating tasks when possible.
It may help you to use software to remind yourself to take a break from your keyboard.