According to Wikipedia: Ergonomics is concerned with the ‘fit’ between people and their technological tools and environments. It takes account of the user’s capabilities and limitations in seeking to ensure that tasks, equipment, information and the environment suit each user.
If you are having problems with various body parts, it may be that you need to adjust/correct your body posture at the computer.
In my recent cybertravels, i looked for information that might be useful in helping you to relieve some of the stress on your body while working at the computer.