During some operations they pump air into the body cavity to make it easier to get to the places they want. i had my gall bladder removed by keyhole surgery, and was told that the pain I had in my chest and shoulders was due to this and it gradually faded away as the gas dissipated.
Diagnosed HEDS December 1st 2005. DD1 (20) HEDS and scoliosis (now corrected by surgery), diagnosed June 2006. DD2 (18) mild HMS. Son (11) some hypermobile joints, poor muscle strength and seems to be developing scoliosis as well, woopee!