What Causes Stomach Pain, Bloating, Gas, Bad Breath, And Foul-smelling Stool Despite Multiple Tests And Diets?

My stomach hurts everytime I eat anything and I’ve tried many diets and tests with doctors and no one has figured it out. Some of my symptoms are bubbly stomach, bloating, gas, pressure, bad breath, foul smelling stool and much more. What could it be I need some answers if anyone can help?