yes staring at the screen for prolonged periods of a time can cause a headache. neck and shoulder muscles can become tense from lack of mobility which sets you up for a tension headache. its is important to take breaks and at least stretch often.
Well, Computers are surrounded from every side of our lives. Specially, people like us! In our practical life, even we get headaches because of any other reason, we blame computers for it because we use it daily and I guess for several hours. But, scientists working in the eye sector of human beings were able to prove that the rays coming out from computer are harmful to our eyes and can create headaches due to this reason. Even I had been told by doctor that my headache is due to the use of computer when I visited my doctor last week. :) Don't stop using computer Chris! You sound to be an intelligent guy! I guess, you are good with computers! So try using modern generation laptops that are eye friendly! Have fun! :)