Facing tense headaches for long time.

For quite some time, Im having an irritating headache that comes from time to time. There is no clear indication when exactly it comes. It could be stress, I first thought it was because of looking at computer screens and devicrs for long time. But I did an experiment and did not look at the screens from 8:00 - 4:00 for 2 days. Yet the headache continues. Funny enough, when I pickup something to eat, the headache suddenly disappears, and I feel calm and normal again, and yet it comes back again. I suffer from myopia if that is useful information. This problem, its very scary and painful, I'm just 16 you know. And I dont want to scare my parents that I have a health problem. I'm not skilled enough to find out exactly what is happening to me. Please help *_*. My brain is not telling me clearly whats wrong with it.