Warning signs of lung disease include a chronic cough lasting at least one month, shortness of breath without heavy exertion and chronic mucus production lasting one month or more, according to the American Lung Association. Additional symptoms include labored breathing, wheezing, coughing up blood and unexplained chest pain.
Chronic cough indicates a problem with the respiratory system, and it is an important early symptom, notes the American Lung Association. Shortness of breath that does not improve after exercising also is a sign of lung disease, as is difficulty breathing in or out. Patients who are experiencing one of more symptoms of lung disease should contact their health care providers as soon as possible.