I have always maitained that these( PPI & H2 blockers ) drugs work for some period and than our body becomes immune to that particular drug. Than there is need to change the salt or , alternatively your doc should look GERD from different angle than to controle acid only with PPI or H2 blockers. Pl. consult your doc. I have similar problems and my doc keep adding or changing drugs. Probably Reglan might be of some use to you as it increases mascular action in stomach. But you should take this medicine only after consulting your doctor. In your case you are alrite when you are active and your muscles are bieng excersied, there seem to be linkage with your GERD and mascular action.
All the best