Have you considered seeing a Naturopathic doctor. There could be increased intestinal fermentations caused by an imbalance in the intestinal flora e.g. too much underlying fungal, bacterial or parasitic infections. When you eat food that ferments a gas
production occurs which can cause a build up
in the abdomen but also can cause "splenic flexure syndrome" in which gas
in the bowel leads to pain in the lower chest or left shoulder.