What Causes Pain In Back Along With Pressure In Chest?

I went to the doctor today because I had a pain in my back and pressure inside my chest cavity. I had some tests done, two of which were an EKG or ECG (I m in Germany and they called it an EKG) which was abnormal and an ultrasound of my heart- the doctor said my heart was normal. However, the doctor that took my EKG said I might have a rare heart disease dealing with electricity. He suggested I make an appointment with a specialist. I am just wondering what my chances are that I might actually be at risk for such a rare and life threatening disease.