HealthDay suggests that you should see a doctor if you have a cough that won't go away.

"Cough is the most common respiratory symptom for which patients seek medical attention," says Dr. Alan B. Goldsobel, chairman of the cough committe at the American Academy of Allergy, Asthma & Immunology (AAAAI).

"Cough protects the body by removing mucus and irritating particles from the respiratory tract. Coughing is a useful function and does not always mean there is a problem ... However, coughing at night, after going to sleep indicates the need for medical attention."

While wheezing and shortness of breath are more commonly known as signs of asthma, a nighttime cough could be a sign of undiagnosed asthma. Some experts think that cough is the most common symptom of childhood asthma.

A chronic cough could also be a symptom of a viral upper respiratory tract infection, stomach or esophagus problems, an inhaled foreign body, or environmental irritation.