I'd see a new gastro.
Fibro makes pain worse, but doesn't cause GERD symptoms. Reflux gets worse when you lie down, especially after eating. OF course pain is in the chest! The stomach is right next to the heart, just separated by the diaphragm. Ask the ER docs. They see GERD masquerading as heart attack all the time!
Since the pain has recently gotten worse, you may have a new or worsening hiatal hernia. Normally they don't cause a problem, but if the stomach gets stuck in the chest (paraesophageal hernia) because of a large hernia, it can be serious.
BTW, a lot of GI docs don't knock you out at all for endoscopy. It's not necessary unless you have a terrible gag reflex. You can refuse anesthesia, although take the throat spray! I would certainly refuse Versed. It does nothing for pain, only gives you amnesia. Then you're woozy and stupid for hours afterward.