Hello, Headache can be caused due to number of reasons. As it is related to watching screens for long time its better to visit eye specialist to check any visionary problem. Headache associated with underlying stress is usually of mild to moderate intensity and not increased by any physical activity. If there is associated running nose, lacrimation, nausea, vomiting, intolerance to voice and light it can be cluster or migraine type. There are good medications available to take care of all types of headache. You can contact me for further help.