Sinuses (sinusitis) is a sinus infection that affects the nasal passages, they become inflamed and swollen. The inflammation comes from the bacteria or virus that caused the sinus infection, either from a cold or the flu. And the swelling makes it very difficult for mucus to drain and so the mucus builds up (causing sinus pressure). That build up of mucus makes it difficult for you to breathe and you become congested. The mucus that is built up in your nasal passages will become thick and yellow or green in color. And you may also experience some:
1. a sore throat
4. pressure or tenderness around your eyes, cheeks and forehead
You may even feel pain right behind your eyebrows or the cheeks from the build up of mucus causing pressure on these areas.