<span>The number of calories you need simply to breathe, pump blood, grow hair, and be alive is called the :
</span>D. Resting Metabolic Rate
Many things can cause shortness of breath, but the most common are asthma, pneumonia, bronchitis, lung cancer, anxiety, an allergic reaction, a lung injury, obesity, heart dysfunction, COPD and many many more things.
As for treating this, see your physician. Hope I helped you!
