Thanks for your question on Health Care Magic.
I can understand your concern.
Yes, you should immediately
consult doctor and get done ecg and 2d echo to rule out heart diseases.
You are chronic smoker and your symptoms are classical of cardiac pain.
So don't wait at home. Rule out heart diseases because this can be life threatening if not treated promptly.
If these reports are normal then possibility of
bronchitis is more.
So quit
smoking as soon as possible.
Get done PFT (Pulmonary Function Test). This will tell you about severity of the disease and treatment is based on severity only.
You may need inhaled bronchodilators and inhaled corticosteroid (ICS).
Don't worry, you will be alright. Quit smoking and rule out heart diseases.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.