I have been having palipiations, chest pain and shortness of breath as well. I had an ECG done on Thursday which showed my heart rate was too high so I have to wear a monitor for 24 hours so they can track it further and get an scan done on my heart. As for reasons they said it can just be one of those things that happen in pregnancy but in my case they think it is anxiety that is causing it. I hope it is nothing serious and you can get some answers today.