I am happy to help you.
Can you tell me if you have any medical problems?
Do you take any medications?
Have you seen your doctor about this?
Are you swollen anywhere?
Has he done chest xray?
What about a cardiac workup such as stress test ?
Do you know what your cardiac ejection fraction is?
Ok. Well you need to have some test run to find out what is going on.
Some possible causes could be:
~blood clot in lungs
~high blood pressure in lungs
~leaky heart valves
~fluid in lungs
~out of shape
~ rapid weight gain.
Your doctor may have some pulmonary (lung) function test done and cardiac.
I would see your doctor right away so you can start feeling good again.
You can read more about short of breath here: