I'm 54 weight 168 and 5 ft 7. I recently started having shortness of breath after short exercising, very short. What should I be concerned with.?

Go get checked. New onset of dyspnea or shortness of breath on exertion may be a sign something serious & needs to be evaluated.
Don't wait. Depending upon your other risk factors, you could have heart disease, emphysema, asthma or any one of dozens of other wild guess diagnoses. Since you have new symptoms, and they can be a sign of something bad, its best to see your doctor soon.