what can cause a feeling of swelling from my throat to my tummy?

[WestCanadaGuy]

I am at a loss an so are the docs.  
I have had random and long lasting sensations of swelling in my throat to my tummy.  I can't seem to pin point if it is my esophagus or trachea that is bothering me.

It is worse if I am laying on my back.  As a matter of fact, I can no longer sleep on my back because it bothers me so much.  

My problem is that no one has been able to diagnose what this may be.  I have had the following:
- Silent reflux treatment (no effect)
- Barium Swallow (nothing that should impact my throat, but it did show a small sliding Hiatus hernia)
- Endoscopy (all clear and no issues)
- Ultra Sound (slightly enlarged Thyroid, but not big enough to cause these symptoms)
- Neck CT (nothing showing in throat)
- ENT nose scope (nothing showing)  

It is driving my nuts and is super bothersome.