This is usually caused by a virus and often persists even after other upper respiratory symptoms are gone. In some cases, bacteria, or rarely fungus, may cause a sinus infection. Other conditions such as allergies, nasal polyps, and tooth infections can also contribute to sinus pain and symptoms. Infections or allergies make sinus tissues inflamed, red, and swollen. Make an appointment with your doctor if you have a fever, nasal discharge, congestion, or facial pain that lasts longer than ten days or keeps coming back.