when you re short of breath it s hard or uncomfortable for you to take in the oxygen your body needs you may feel as if you re not getting enough air sometimes mild breathing problems are from a stuffy nose or hard exercise but shortness of breath can also be a sign of a serious disease many conditions can make you feel short of breath lung conditions such as asthma emphysema or pneumonia cause breathing difficulties so can problems with your trachea or bronchi which are part of your airway system