Can intestines & esophagus feel pain? i.e. if you swallowed a fish bone even a small one, & it stabbed or scratched, would you feel it? or not know?

Not after a point: The intestines only have stretch pain fibers, so they would not "feel" a stab or poke. Your abdomen would feel the inflammation created if something caused a hole or infection. The upper esophagus may give you a bit more sensation, but once it's in the stomach, only thing you would feel is stretch pain (like after eating at a buffet), so a bone would not cause mush sensation at all.