I have brain tumor or just allergy headaches?

Not usually tumor: Surprisingly,headaches are not normally initial symptom person experiences if a brain tumor. Symptoms, like seizures, changes in vision or hearing, weakness of the arms and legs, or cognitive decline are often the first symptoms.Chronic headaches are likely to be related to other, less serious conditions like migraines, allergies, or common vision problems that require glasses or contact lens.

Brain tumor: I would need more details of what the symptoms are to answer this question - allergies are clearly more common than brain tumors.

Allergy or tumor: I vote for allergy. Get tested by a neurologist and if tumor is ruled out you can get some lab tests for allergy. I use great plains lab for that.