Can shortness of breath be from blockage of heart?

Yes: Lot of patients don't get pains and instead complain of shortness of breath due to blockage in arteries of heart.

SON: Your symptoms may be from blockage in the heart's blood supply vessels (coronary artery disease) or lung disease and need to be evaluated. If symptoms are worsening, go to the er without delay! if they are stable, then see your doctor soon.