Yes spending too much time, in the wrong position can cause pain in various parts of the body. I'll give you a link and its best you have a good supportive chair and computer desk that you can adjust to your specific needs. The chair should be supportive and at a height where your feet are flat on the floor and knees level with the hips. Be aware of your arms being comfortable while typing and your screen should be in front of your eyes - so you're not looking up or down.

Take breaks often and do some arm circles and bring your arm across your body and hold with the other arm. Cross both arm to opposite sides as if you're hugging yourself - gently stretch your head from side to side as tolerated. Now I'm not doing all these things because I have my laptop at the dining table lol. If someone doesn't have one of those adjustable chairs - they can use a shoebox for their feet. One problem I get is a sore tail bone. I think many people spend too much time, especially young people and see the bodies are suffering - more children over weight.

http://www.care2.com/greenliving/9-e...r-sitting.html