Let me know what happens.
I got over fear of flying with a simple mild hypnosis, which was really just focusing me on reality (the plane seat is comfy and I enjoy being at the destination) and away from disreality (I am not an African dictator so no one wants to blow me up.) In your case the reality is the test results showing you are powerful and healthy and the disreality is wondering if some undiagnosed health issue is lurking out there.
I don't want to reach meds. So I will take ur advice and focus on the results. I read the article. Very good one too. Thank you. Thank you for taking the time to msg me.
Look around at other posts on this board where the people are sure they have heart problems and realize those other people don't have heart problems like they think they do, likewise for the CNN guy and realize the same applies to you. From there try to focus on the test results instead of the twitches and the anxiety might be relieved. If no success, then try counselling and if it doesn't work likely you will have to go to doc for meds.
The chances of heart problems at your age are slim and your tests have told you there is no problem. If you can't accept the tests I suggest counseling or other alternatives like reading philosophy books, otherwise you sound like you will have to go to doc for the only solution they have, meds.
Pain in your left back can be from anything but surely has nothing to do with your heart. I wallclimb every other day and am constantly adjusting my workouts to compensate for ouches that don't appear at all times of the day. Pulling too hard on something, a quick tug or over-analyzing your body due to anxiety to the point that every ouch is treated as a clue to a mystery heart disease could be reasons you have back ouches now. Anxiety works like that, always poking at you to make you worry.
2 years ago I went for an ECG when my "heart symptoms" got to be too much for my mind to deal with and they said I had no problem. I stopped worrying after that diagnosis and had no issues since, but some people can't accept that like the guy in the CNN article I posted.
Some people just can't get rid of that fear. Read this.
http://www.medhelp.org/user_journals/show/857117/CNN-article-about-anxiety-sufferer?personal_page_id=308570
For others counselling might help you resolve your fear.
But first, how old are you? It isn't filled in your profile.