A cold can leave you dealing with a stuffy nose, sinus pressure, and thick mucus for days. But what happens when your other symptoms improve and your congestion refuses to go away? Lingering nasal congestion is common after a respiratory infection, but it can sometimes signal a sinus infection, allergies, or another condition that needs medical attention. Congestion can last longer than a typical cold, but symptoms that persist, worsen, or return after improving may ...