There are 4 sinus cavities such as Ethmoid sinus cavities, Frontal sinus cavities, Maxillary sinus cavities, and Sphenoid sinuses. If the paranasal cavities are inflamed, it can lead to infection.

The inflammation of nasal cavities builds pressure in the region leading to pain in the cheek area, eyes, nose, on one side of the head (temple areas), and severe headache.

There can be several reasons for sinusitis such as infection, allergies, irritants, and chemicals. Usually, sinus infections are not contagious.
Read more- Are Sinus Infections Contagious? Sinusitis Symptoms and Home Remedies