Allergies and pathogens
For many people, persistent or frequent exposure to allergens, viruses, bacteria, and germs is the cause of their everyday headaches and facial pain. When the sinus cavities and the mucus-lined airways inside the nose and skull get irritated, they enlarge and hold mucus rather than allowing it to drain normally. This is how allergies arise. The swelling causes throbbing or constant pain and sensitivity in the head, cheek, eye, and forehead regions by raising the pressure inside the sinus cavities and airways and blocking normal airflow.
Allergy-related headaches are more likely to occur in people who have nasal congestion, untreated sinus infections, viral or bacterial infections, or aberrant internal nasal structures. It is a very common cause of daily sinus headaches.