Hello. Welcome to hcm.
is a disorder which causes reflux of gastric contents leading to pain,burning sensation in chest. Lower sphincter is lax and so part of stomach has also entered to chest causing hiatus hernia
. It is very unusual to find fecal matter in mouth. It could be two reasons. You might have a pouch in throat where is food is getting collected called zenkers diverticulum or you have a abnormal connection between stomach and colon
I advice you to undergo barium meal
test and ct scan
abdomen to find out abnormal connection in your colon and get it corrected surgically.
All the best