Shortness of breath, Difficulty breathing, Wheezing

Shortness of breath (dyspnea) has many causes affecting either the breathing passages and lungs or the heart or blood vessels. Doctors classify dyspnea as either occurring at rest or being associated with activity or exercise. It is also useful to know whether dyspnea occurs gradually or all of a sudden. Each of these symptoms helps to detect the precise cause of dyspnea.
Shortness of breath has many different causes. A blockage of the air passages in your nose, mouth, or throat may lead to difficulty breathing.
Heart disease can cause breathlessness if your heart is unable to pump enough blood to supply oxygen to your body. If your brain, muscles, or other body organs do not receive enough oxygen, a sense of breathlessness may occur. Sometimes emotional distress, such as anxiety, can lead to difficulty breathing.