@stephieisabella I am not familiar with gastroscopy, I did google it, but not sure from the results if this is like an endoscopy and more. I had an endoscopy which showed Barrett's Esophagus. Is that possible for you?
You are young but my husband's granddaughter went through similar at about the same age. She does have to take antacids before eating but seems to be doing well. I hope you are able to diagnose the problem and get some help with it.
JK