The way I use my computer, I have it sitting towards the back of my desk. That way, when I am typing, my whole arm (from elbow to wrist) is resting on the desk and that prevents too much of load coming to the shoulder or neck.
My office and a lot of offices have the option to get an ergonomic evaluation done by an expert. He/She comes out asesses your work habits and situation and then reccomends products which can help with your particular concerns. Maybe you could look to see if your work provides this option?