Last week I was having unexplained chest discomfort so I went to Dr. Explained what it felt like. He then gave me a ekg and said it looked normal. Today, I've been having shortness of breath but no other symptoms. I am a smoker and earlier in day I was very anxious and pacing a lot. However at times of breathing issues I wasn't. Since heart issue was ruled out by ekg, could it have been anxiety from earlier in the day?