Not sure where you are on your journey...
LPR, GERD, and gastritis can cover a broad range of possible causes. For many people, which is what doctors are used to dealing with, the problems are simple. Poor diet, overweight, drugs/ medications that irritate the stomach. etc. For these, a short course of PPI, dietary changes, not laying down after eating, and symptoms usually resolve.
The next level, if symptoms do not improve, is endoscopy, tests for h pylori, and possibly SIBO. Depending on symptoms, an empty test for gastroparisis may be needed. If something turns up here, you may find improvement from conventional treatments.
But for some of us, the problems extend beyond, and conventional medicine is almost useless.
There seems to be a great deal of LPR/ GERD/ gastritis/ gastroparisis attached to ME/CFS. The speculation is either a viral component is responsible (in my case enterovirus), or vagal/ neuro damages from a previous virus.
I have terrible LPR, you are not alone.🤮