If you've been coughing and wheezing a lot this winter - it could be more serious than you think.

Millions of people suffer from a variety of respiratory problems without getting a proper diagnosis and treatment. Dr. Akshay Sood, assistant professor of pulmonary medication at SIU School of Medicine in Springfield says respiratory problems can be caused by some serious diseases. He says respiratory problems occur most frequently during the winter. He explains:

SOUND BITE: ". . . the flu season becomes a prominent cause of respiratory problems in the Winter. And also in the winter everyone has to stay indoors and when everyone stays indoors, the air within the house is a very potent mechanism of transmission of infections and other problems."

Dr. Sood says the most common symptom of the flu is a cough. The cough may be dry, or it may be productive with phlegm. The phlegm may white or yellow, or it may contain blood. When you cough up yellow phlegm, it usually suggests a bacterial infection. He explains other symptoms:

SOUND BITE: ". . .the other common symptom we see is shortness of breath. Initially, shortness of breath becomes evident only with activity -- vigorous activity. And then as the disease progresses, shortness of breath becomes evident even with mild activity and sometimes even at rest. The other common symptoms that we see of respiratory problems include chest tightness, wheezing, chest pain, fever."

Dr. Sood says if you have had some of these symptoms for more than one week or if are coughing up blood, you need to see your family doctor for diagnosis and treatment. These symptoms could be an indication of allergies, asthma, bronchitis, emphysema, or even lung cancer.