Why does my head always hurt when i get on my computer even when i havent been on long?

btw ive never had this happen before and ive never had high blood pressure,im 209lbs,17 years old,i have a shunt in my head because of buildup of water on my brain when born to keep it from being to built up,and thats about it oh and i have a chairi malformation where the brain goes in to my spine though a hole thanks in advance!