Hi. the symptoms you are explaining, as associated with postural change are mainly concerned with musculoskeletal system of yours..and in addition u r diagnosed with GERD
, in which the symptoms will be burning pain in upper abdomen, like you said in the centre of your rib cage
, except postural relation might not be there. so, hot fomentation ( hot water bag application), muscle relaxants, and avoiding pulling heavy weights will help.. in addition to this continue takin Omeprazole
and take care of your diet accordingly. avoid tea, coffee, spicy food. adequate amount of water intake is adviced. take care.