see a doctor.

The most Likely cause is dehydration. You might think that you drink plenty, but everyone has different needs, you might just need allot of fluid.
Try upping your intake of liquid. During the time your doing this drink only water, perhaps a little fruit juice and maybe unsweetened green tea.
Steer clear of anything dehydrating like alcohol, anything sugared, or caffeine/caffeinated/decaffeinated.
Try this for a couple of weeks and I’m guessing it’ll set you straight.
I used to get the same. I really dislike drinking water, and basically do everything else wrong. Once in a while I get the head aches back. I do the above and it sets me straight until the next time I forget to live right.
If after a week or so you’re not feeling better, go see your doctor. This could be a symptom of something serious.

My dear you just have a sinus headache that can be caused by a cold, a change in pressure, or sinusitis (sinus infection). You should go to your doctor because if you’re having more than one sinus infection a year and they’re not going away you need to try a different treatment. I hope you feel better soon, try some green or peppermint tea or sudafed to relieve the pain until you get to the doctor.

Probably a sinus headache. You have sinuses in your cheekbones, around your nose and above your eyes/forehead. See a doctor if over-the-counter decongestants don’t work. Try alternating hot & cold compresses to get them drained out.