Hello Headache could be due to stress, high blood pressure etc Grittiness could be due to dryness A. Take proper rest B. Cold compresses help C  use lubricating eyedrop like lubrex eyedrop frequently Consult local ophthalmologist if problem persist

If there is no vison change no need to panic. Pls follow the general instructions. 1.Frequent blinking of eyes 2.For every 20 minutes look far away for 20 sec 3.Drink more water 4.Do not sit in front of air conditioner 5.Take Adequate break in between 6.computer screen should be 16-30inches away 7.ensure the screen is neither too bright nor dim 8.get good sleep 9.cold compression with any wet gauze in case of eye strain 10.ensure there is no glare from your screen.