Yesterday I had a lot of stress in the morning, right after that I started feeling chest pain and also back pain , directly opposit to chest pain site. It was not too strong, but in the late evening I went to ER, they did ECG and chest x-ray , and said both were OK. The doctor also said that the way I described it, like pain is worse with deep breath , it does not sound like heart problem. Today I went to work and now I am in even greater pain. Can it still be heart even if ECG was good yesterday ? What else can it be?