On another forum (car related) I go to, someone posted a link about how PPIs can lead to magnesium deficiency. The person noticed that after taking magnesium for a few days, their pain symptom -- it was like joint pain or muscle pain or something -- went away.
So at that point I tried it; I had already bought a bottle of Magnesium Citrate I just wasn't taking it. But I had increased my dose of PPI to 40mg a day, now 80mg a day, and had experienced some neck stiffness that I'd never experienced before. A few days after starting the magnesium, it is basically gone.
Placebo effect or not, I don't know. But my gerd/lpr symptom (voice issues, tight throat, bitter taste in mouth) did not change when I started taking it. It certainly didn't make it worse.
So it would probably be worth a shot, especially if you have any unexplained stiffness or pain and are using a PPI.