I work on computers, building and fixing them, day and night and I get headaches and stiffness too. Especially around the temples and eyes. Too much strain.
when I go on the computer I feel the same way you do cut back on the computer and you will feel better. Do you go out and get fresh air? Go take a walk that would help.
Very very unlikely. Everyone (well nearly everyone) gets headaches and stiff necks. Calm down. I hope your 24 7 computer use is not searching health stuff.