I have been experiencing severe upper back, rib and chest (side and frontal) pain, on both sides when I run. I had an ECG and Stress Test 2 weeks ago when the pain was bad. Both tests showed everything was normal in the heart although I was not experiencing the pain during the stress test. Could this still be heart blockage? I do have high colesteral although controlled with statins over the past 10 years. If not my heart, what in the world could this terrible pain be caused by, if not my heart. My lungs also checked out in the ER visit with an x-ray. It only happens when I run, not bike or other exercise.