Alexander Technique teachers instruct, demonstrate, and coach people how to use the computer without injury. If people are in pain we teach them how to stop injuring themselves, and the steps to take to allow the body to heal.
Let's try something right now. See if you can notice any tension in your neck. It's there, though you may not be able to sense it right away. You can learn to let these muscles go. If you release your neck muscles, your head will rotate forward, and move up. You could think this way: I want my neck to be free so that my head will move forward and up. This 'forward' business doesn't mean forward as in your face moving towards the screen...