Many uses of computers can cause problems. I recall using a bad chair while writing a book. I could barely move during that time. Now I use a nice expensive chair and it makes a lot of difference.
Had the same experience with a computer mouse years ago. Started noticing changes in my hand so I switched to a Logitech Trackman Marble and the hand changes ceased.
Article in the Daily Mail about laptops causing back problems in users. Here is a quote:
Millions of others are at risk of “irretrievable damage” to their spines, necks and shoulders because of poor posture when using laptops, it was claimed.
The main specific problem mentioned in the above article is bending and straining to look down at your laptop monitor. The same problem exists on desktop systems. Make sure you monitor is high enough that you don’t bend your neck to see your screen.
I am tall and have to raise the monitor quite a bit. My preferred method has always been a stack of phone books. Cheap, easy to locate, and you can easily scoot the monitor around on the desk should you need to.