Why Do I Have Stomach Bloating And Discomfort Plus Feeling

Why do I have stomach bloating and discomfort plus feeling I'm going to regurgitate whenever I bend over for more than a minute, to do something like weeding the garden? I have GERD which I take a PPI daily but my symptoms when bending over don't produce acid reflux although eventually I spit up foamy saliva which is not vomit and isn't accompanied by heartburn. The symptoms go away in a few minutes if I stop bending over.