Thanks for your question on Healthcare Magic.
I can understand your concern.
Yes, you should definitely visit emergency room and rule out heart diseases.
You are a chronic smoker, having left sided
chest pain, breathlessness on exertion, all these are commonly seen with heart diseases like
heart failure and coronary
artery disease (CAD).
So immediately
consult doctor and get done blood pressure monitoring, ecg, 2d echo and
stress test (trade mill test) to rule out heart related diseases.
You may need cardiac supportive drugs on the basis of these reports.
Don't worry, you will be alright. But don't wait at home, consult doctor as soon as possible.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.