Bronchitis is an infection or irritation of the bronch i- the passageways from the windpipe (trachea) to the lungs. Pneumonia, by contrast, is an infection or irritation of the lungs themselves. Both of these conditions are much more common in the winter, as they usually follow an upper respiratory tract infection (cold).
Bronchitis usually manifests with bouts of coughing, shaking, chills, fever, and chest pain that are usually preceded by an upper respiratory tract infection (cold). In addition to the symptoms of bronchitis, pneumonia shows classic signs of lung involvement, including shallow breathing, coughing, and abnormal breath sounds, and a chest X-ray shows infiltration of fluid and lymph into the lungs.