Thanks for your Query,
Your chest pain
radiates to shoulder & arm is more during exertion? is it associated with perspiration?
Is it relieved by taking Sorbitrate
tablet.? If yes then the chances of it is cardiac pain.May be Angina.
on back has no relation with this pain but some times herpes
infection mimics cardiac pain & it starts with bruising.
So consult your doctor he will take ECG & guide you accordingly.