I'm 52 and I have had those symtoms for 20 years.
After numerous tests, I'm fit as I cycle 125 miles per week, we have one important common fact, I spent and continue to spend extensive time on the PC. Compounded this with an assumption since you send so much time in front of a computer, you also my be a Type A personalilty . Her is what I have discovered. It's very common with extensive PC users; related problems mainfest diferently
Bottom line anxiety
and chronic eye strain; both feed upon each other. People are not designed for such extensive periods in front of a PC. You must change you life style on how you do your work. Many many eye breaks by moving away form screens as the eye muscles become lazy and limited and eye exercise. If your are Type A, you are phychosomatically reacting to stress; meaning you are tensioning facial (eye) muscles whilst working. The cure is the ancient art of meditation
'whilst you work', i.e you literally audit your body and by breathing, remind your body how to relax
This I determined what happens to me and the techniques above have not entirely elimante the problem but I can manage it. The permanent solution is get off the PC for a year and enjoy your one life; the systoms wil eventually go and then manage your priority in this electonic age