Thank you for your help! It great apprecaitated!
Hi, welcome to the forum, we cannot say for sure for now. Firstly migraine has to be ruled out which may have a triggering factor like specific food, smell etc. The next step would be to undergo CT of brain or/and lumbar puncture. These two investigations are vital for the diagnosis. The conditions which have to be ruled out are Giant cell arteritis, ruptured intracranial aneurysm, brain tumors etc.
Allergy can be a possibility i.e. secondary to rhinosinusitis. Sinusitis is also associated with pressure in head. In such case antibiotics o control infection, anti histaminics and drainage procedures are helpful.
I suggest you to consult a neurologist. Take care and regards.