Thanks for your question on Healthcare Magic.
I can understand your concern.
Mild Breathlessness, skipped heart beat, left sided
chest pain etc can seen in
arrhythmia (rhythm disturbances in heart).
So first get done ecg, 2d echo and Holter monitoring (24 hours continuous recording of ecg).
If all these are normal then no need to worry for heart diseases.
In my opinion, your pain is mostly due to musculoskeletal cause.
So avoid heavyweight lifting and strenuous exercise. Avoid movements causing pain.
Avoid bad postures in sleep. Apply warm water pad on affected areas.
Take painkiller like
ibuprofen. Sit with proper back and chest support.
Don't worry, you will be alright with all these.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.