Collapsed lungs can be serious and not as serious and depends on how bad the collapsed lung is.
If you do have a collapsed lung or even think you may have a collapsed lung you need to seek medical attention so the doctor can determine how bad the collapsed lung is.
Signs and Symptoms of a collapsed lung include sharp, stabbing chest pain that worsens when breathing or with deep inhalation that then often radiates to the shoulder and or back; and a dry, hacking cough.
Collapsed lungs that are really bad can be fatal so you should always seek medical attention for the collapsed lung just to be safe.