I'm sorry you're having such a difficult time right now. These symptoms can be scary with chest pain and all. You indicated you eat well and that's a great start with helping GERD symptoms. But, sometimes just eating well isn't enough, you have to alleviate offending foods, and there are many, unfortunately for some of us. Half my battle with GERD is trying to figure out what foods I can eat, and I'm also relatively thin.
Alcohol for some of us can also trigger a flare, and especially Champayne. Bubbly.....full of acid. I use to really enjoy a glass of fine wine and bubbly on occasion, but my body rejects them. Sometimes, the gas can last for days after consuming some offending foods or drinks. Try something for gas and see if it helps your symptoms.
I've suffered reflux problems for many yrs and had a Endoscopy approx 3 yrs ago, but regret to some degree not getting one yrs ago. Like you, I was a little afraid of the procedure, especially anesthesia. I kept telling doc while lying on the table that I didn't want to go under, and hubby kept telling doc to put me under. Doc put me under and when the procedure was completed, I had awaken unaware of procedure being conducted still telling doc I didn't want to go under.....LOL So, it didn't take long, approx 15min, and I didn't have any problems afterwards.
I hope your symptoms subside soon, and let us know how your doc appt goes...BTW, some GERD sufferers have had success with decreasing their carb intake.
Gentle huggs to you....