What exactly is sinus infections and how do we get them? why do they return? is it possible for it to be bronchitis

Sinuses: The paranasal sinuses are cavities in the skull lined by ciliated mucous membranes. They connect to the nose and throat. When they are partially obstructed they can become infected and this is called sinusitis. Bronchitis is completely different, and involves the passageway into the lungs.

Infection of nose: The paranasal sinuses are air containing cavities in the face. They become infected with virus usually arising from the nose, for example, a cold. Most of these infections resolve without an antibiotic. The symptoms are classically pain and pressure in the face and have nothing to do directly with bronchitis except they may occur together. Recurrence can be due to allergy or a blockage.

Smoking : If you smoke tobacco or mj, you will have an increased incidence of both sinus infections and bronchitis. The commonality is smoking interfering with surface immunity in the membranes of the sinuses and/or bronchial tubes.