Thanks for the query to H.C.M. Forum.
Age is very important factor in this case , as these symptoms may be due to many reasons.
No doubt you mentioned that blood work done, but normal and this is a good thing.
In many ( most of cases) , if blood is taken immediate after any attack , it will not yield any abnormality.
So get in once again blood examination and E K G , upload these reports .
Also mention the age as hormonal
imbalance may be another cause.
Hyper acidity and tension are two most important reasons of this type of symptoms.
Physician consultation may help you.
Get well soon.