During the cold and flu season, many people develop chest congestion and a cough. The cause of a cough is usually due to excess mucus in the airways. Anyone can develop a cough and while it is usually attributed to a cold or the flu, it can also be caused by smoking, asthma, or other airway obstruction diseases. Coughs can be treated with over the counter medications but if they are severe or do not go away after several weeks, a doctor may need to be consulted. There are stronger, prescription medicines that can treat a cough. It is always a good idea to drink plenty of fluids to thin the mucus when you have a cough.