I have been diagnosed with Polycythemia Vera, heart failure, and a left bundle branch block, I have been in and out of the hospital E.R., they say its a chest wall? I don t know what that is, and I have had 4 heart attacks this year already, and my EF is 40%, I am having chest discomfort again now but not sure how to tell the difference between a heart attack and a chest wall? Can you help me understand?