I was diagnosed with GERD but had no symptoms, the GI just said I "probably had it" and put me on a PPI which was terrible. I did have a small sliding hiatal hernia, which was discovered during a scoping. I did tons of research, and there are articles on how to adjust a hiatal hernia, but I never tried it myself. I found a chiro who is about an hour north of NYC who specializes in adjusting hiatal hernias. I was desperate to try anything, so I did, and it resolved all of my issues after 6 sessions or so and this was proven after a second scoping and a barium swallow test. I also lost some weight during this time which both doctors agreed must have helped.
These aren't from my Dr., but helpful websites. I had anxiety and heart palpitations that went away after treatment (and after some magnesium supplementation - so who knows).
I don't know if it would work for everyone, but it definitely worked for me. I go in about every 8 weeks for "maintenance" and peace of mind, though my symptoms are all gone. Not on any drugs or PPIs.
As DIY suggested, a lot of people recommend wedge pillows for GERD or hiatal hernias.