Danielson, I was also in a car accident and sustained neck whip lash without head trauma. I can tell you from my personal experience the shortness of breath and a pressure on your chest can be caused by anxiety. I've had almost every test done you can think of and the results always came back negative for any problems. It's been 2 years since my accident and thankfully my condition hasn't gotten any worse but I have seen an improvement over that time frame even if progress has been minimal.