can get trapped in the fundus of the stomach
(look up a picture on google to find the
fundus). Since the
fundus is on the
left side of the
body, and gas rises, it pushes up from the stomach through the diaphragm (it doesn't penetrate these structures, it only pushes on them like if you take your fist and push it into an inflated balloon). This can irrate the vagus nerve, or even the phrenic nerve that controls the diaphragm, if it puts pressure on these major nerves.