Hi!
I had gone through your query and understand your concern.
If I were your treating doctor and had come to me with these symptoms I would first ruled out two possibilities :
-The first possibility is
heart disease and since your symptoms are going on more then 20 years and your test results are normal I would exclude heart disease.
-The second thing I would ruled out is
gastroesophageal reflux disease which is a condition when the stomach acid moves up into the esophageus.the symptoms of this condition are
chest pain or burning upper
abdominal pain ,worse when lying flat or banding over,particularly soon after meals,relieved by antiacids or sitting upright.
You can try taking a PPI drug (Omeprazol) for some days and if your pain is relieved it serves also to confirm the diagnosis.
If this doesn't work I think your symptoms are due to nervous tension,
anxiety .
This can happen and is one of the ways that our brain use to handle with nervous tension and everyday problems by transforming them in organic complains.
In this case you need to try to lower the anxiety in your life for ex you can avoid situations that cause you
stress,you should do things that you like,maybe you can try
meditation.
If this things doesn't work your doctor can prescribe
you a anxiolytic drug and see how this will go.
Hope I was able to help you.
Take care.
Dr.Rovena