hurts when i breath on upper back side left

First your age and health would factor in on a diagnosis or prognosis.  Heart attack reins supreme in cases as yours.  Then an upper resperiatory infection could be culpart.  As well as side pleurasy.  That is where you cough or breathe the lung lining rubs and becomes irratated.  I still 100% say see your doctor ASAP.  No need to wait.  The sooner you go the sooner you get relief either way.