Thanks for your question on Healthcare Magic.
I can understand your concern.
Your all symptoms, left sided
chest discomfort, irregular heart beats, breathlessness etc are more suggestive of heart diseases like coronary artery disease (CAD),
arrhythmia,
heart failure etc.
So better to
consult cardiologist and get done blood pressure monitoring, ecg, 2d echo and
stress test (trade mill test).
If all these are normal then no need to worry for heart diseases.
Sometimes excessive stress, anxiety and panic disorder can also cause similar symptoms.
So avoid stress and tension, be relax and calm.
Don't worry, you will be alright but first rule out heart diseases.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.