That does seem worth checking out.
My first thoughts are that you may have an enlarged thyroid gland or thymus (in the chest). Also I have read that a prolapsed mitral valve in the heart, makes lying on the back difficult and symptomatic.
I'd ask the doctor to check for long QT syndrome(heart). Amitriptyline is a drug which can make this worse, and it is potentially serious. (and sometimes deadly)
Amitriptyline also causes dry mouth and throat. You might try a drug free period, to test this out as well.
Drugs always have a dark side, and should be evaluated always when problems occur like this.
__________________
All truths are easy to understand once they are discovered; the point is to discover them.-- Galileo Galilei
************************************
.
Weezie looking at petunias 8.25.2017
****************************
These forums are for mutual support and information sharing only. The forums are not a substitute for medical advice, diagnosis or treatment provided by a qualified health care provider. Always consult your doctor before trying anything you read here.