Pneumonia often starts with symptoms typical of a cold or upper respiratory infection, like sore throat, nasal congestion, and cough. As the infection develops in the lung, high fever is apparent along with chills and a cough that produces thick sputum. Chest pain can occur if the outer layer (pleura) of the lungs is involved in the inflammatory process. The skin color may become bluish or purplish if there are insufficient levels of oxygen in the blood. Nonspecific symptoms that can accompany pneumonia include headache, muscle aches, fatigue, and weakness.