Hello @cosimax505, welcome to Connect. I'm sorry you are hurting. I came here too when I was stressed, frustrated and not knowing answers to health concerns, nor did doctors. Thank you for such a complete, detailed list of your search. It's pretty scary when your life is invaded with uncertainty.

I'm no doctor but your overwhelming description fits well with Central Sensitization Syndrome (CSS). CSS is an upregulation of the central nervous system which can affect your whole body from chronic joint, muscle, nerve pain to sensory issues from sight, sound, smell, touch, causing a multitude of symptoms from gut, esophagus, heart etc...

When a body is under such stress and distress, it goes into a fight or flight mode. The parasympathetic nervous system goes into overdrive. It all stems from the brain and antagonizes the body.

There is help for this. I'm attaching a video by Mayo Clinic's Dr. Sletten on Central Sensitization:
https://youtu.be/8defN4iIbho
Perhaps something will resonate with you. If no firm diagnosis presents itself, you will have this in your arsenal. Do you mind letting me know your thoughts after watching?