Stool that is pale or grey may be caused by insufficient bile output due to conditions such as cholecystitis, gallstones, biliary dyskinesia, giardia parasitic infection, hepatitis, chronic pancreatitis
, or cirrhosis. Bile salts from the liver give stool
its brownish color. If there is decreased bile output, stool is much lighter in color.
Reflux can be a symptom of some of these as well.
Personal experience: I was getting the same thing, heartburn, pale stools, etc.