A cough can be a fairly common side effect of lung infections, and those who smoke often usually experience a pretty nasty cough. However, among non-smokers, a persistent cough can be a sign of a much more serious problem. The average cough should disappear within 3 to 4 weeks, though some pulmonary viral infections take longer to heal. If you are suffering from a cough and shortness of breath, it's important to get checked out immediately. Not only could the cough be the result of a serious infection, but it's possible that it's a symptom of lung cancer. Unexplained coughing is one of the problems caused by cancer in your lungs. [caption id="" align="aligncenter" width="595"] Source: cremhel.com[/caption] The cough will usually be a bit dry, and it will feel like hacking. It shouldn't feel like you are trying to cough up phlegm, but there will usually be a nagging irritation in your lungs and in the back of your throat. Definitely something to be concerned about, and a reason to visit the doctor!