I'm sorry that you are going through this.
My father (64 and in good health) has been experiencing chest pains and like you had an abnormal echocardiogram, they too sent him for a treadmill test.
The original echo showed he had a murmur, the doctor didn't seem overly worried but sent him for the extra tests too. They said he may have always had the murmur but as he has been having chest pains to get it checked.
He had his treadmill test just after Christmas and recently went to see the consultant for the results.
Everything was normal his cholesterol too, they said he may have either pulled a muscle in his chest that is going to take time to repair or he may have severe indigestion.
However, unlike you his only symptom was chest pain, if you also have shortness of breath and light headedness you are bound to be very worried. And you don't just have to put up with it, you can ask for a second opinion or at least ask them what the cause maybe if its not the heart.
I hope you get some answers x