Forreal,
I'm sure most of us here have been where you are now. I,too, worried that I was having a heart attack and had tests ran and doctors also reassured me that I was fine. If I were you I would relax and know that doctors are well trained to detect problems and that they did all the right tests. I would say, with confidence, that if they did those tests and they came out fine, then it is most likely your anxiety. Anxiety is very powerful, it can manifest itself in your physical health causing symptoms like chest pain, numbness/tingling, shortness of breath, dizziness, faintness, racing/pounding heart, and the list goes on. It would be wise for you to exercise, eat healthy, do some breathing exercises, and stay away from the internet because it only helps feed those anxious thoughts (I say this speaking from experience, any little thing I run to the internet and look up all the bad stuff that it could be). Also, work through the program and try to challenge your anxious thoughts. Good luck with everything and I hope this helps. Just try not to let the fear and worry take over. But know that you are not alone in experiencing those things.