However, because I now use a computer so much more, my neck and back have started hurting more. I am not overweight and exercise every single morning and take walks every night. I now have a sit/stand desk, so I can stand if I want. I use a large screen too.
You are tilting your head up or down when you look at the screen. Common problem. Raise or lower your monitor so you are starting straight ahead.
[/q
I saw a youtube video with this and it really works also occasionally stretching your legs and cushions helps.