Brief Answer:
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Detailed Answer:
I read your question carefully and I understand your concern.

It might have been useful if you had provided some more info such as the manner of onset (gradually increasing or very sudden reaching maximum intensity in a matter of seconds/minutes), character of pain (pulsating, pressure like, tightening etc), other accompanying phenomena like nausea, vomiting, sensitivity to noise and light, fever etc, other conditions you might have.

Judging from the location of that headache I would say that the most likely cause is sinusitis, inflammation of the bony cavities in your skull, in the case of frontal sinusitis in your forehead. If you have a stuffed, runny nose as well it would be even more likely.

Another cause could be high blood pressure which can also manifest such persistent headache, although more commonly in the back of the head. So some blood pressure measurements are advised.

Tension type headache, the most common primary headache (primary meaning with no identifiable cause) is also a possibility, but if this is the first time you experience such headache unlikely as it usually appears earlier in life.

Brain related conditions in the absence of other signs such as weakness or numbness of the limbs on one side, balance and coordination issues, double vision or visual loss, confusion and behavior changes etc, are less likely. However if the symptoms persist and your primary physician finds no cause such as the ones I mentioned head imaging would still be advised to exclude brain lesions like tumor or stroke.

I remain at your disposal for other questions.

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