last year I had similar issues when I was struggling with my candida ...what was amazingly helpful was oxygen Colon Cleanse and vegan vegan digestive enzymes that were recommended by the candida experts. the heartburn was gone in 2 days, food sensitivities , shortly after (I modified my diet per their recommendations too).
since then the colon cleanser and vegan enzymes became a staple in our family. here's the link