Yellow diarerreah , burning in upper left stomach and sometimes in upper back i was told i had gerd , and bacteria overgrowth why yellow stools?

Pancreatic: Could be pancreas. Yellow stools, oily, floating stools. If pain discomfort worse with high-fat meal, could be pancreas. If told you have bacterial overgrowth syndrome, you need to be treated. You would have likely had a breath test for this. They would likely treat this if you had it.

Yellow stool: The color of the stool usually depends on diet and is not diagnostic of any illness. Presence of blood or dark tarry stool will indicate a GI bleed. While excessive fat or split proteins in stool will indicate malbsorption