system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why sometimes when my nose is stuffy and I blow it, nothing comes out? What is it stuffed with?
gpt
Your sinuses are a series of passages and chambers spread through the center of your face. These passageways can get swollen from allergies, weather changes, irritants like smoke, infection, etc.

There doesn't have to be any discharge for your sinuses to be swollen. NSAIDs are pretty effective at reducing swelling in that area. There are also clever breathing techniques that can clear the swelling. Sometimes simply taking a brisk walk can help clear the sinus by stimulating your lymphatic system.