anyone know what this is?

I ONLY GET THIS WHEN IM LYING DOWN , USUALLY AT NIGHT. When i go to bed, feels like there is trapped gas in my stomach (upper left quadrant), and feels like my stomach is "pulling in" and pressure near the sternum/stomach, weird feeling of discomfort, bit of nasuea/vertigo sensations, when i try sleep on my sides it feels like my stomach is being "drained" and i washing machine feeling as if contents is moving around or being digested, i went ER last week and they said its just torn muscle from working out, and nothing to worry about they said it also in relation to my acid reflux symptons, since i came down with acid reflux 6 months ago due to ulcer and my anxiety condition, i dont have ACID REFLUX BUT ANYMORE THO NOW I JUST HAVE THIS, what is this? THERE IS NO PAIN ASSOCIATED, just this wierd "pulling" sensation, like my stomach is "Dipping in" pushing inwards, i dont do it on purpose something is diffidently pushing/pulling my stomach in, and abit to the left, its not really a bloated feeling its more opposite, the left side on edge of my ribs will be puffy abit, docs said its just the muscle attatched to the rib swollen, but it sticks out more then the right (Only noticeable if i relax and breath in)

No fever
No loose/dhiahra stools
No Pain
No blood in stool /
No Vomiting
No dizzyness

Just nasaea, vertigo falling sensations, passing wind and having to burp along with the pulling/tight sensation

All symptons disappear if i stand up and walk around, or keep myself busy (occasional nausea but not noticeable)

Was thinking maybe stomach distention? Could it be Bile or stomach ulcer is stil there? or anxiety? or is it just trapped gas? any idea's?

Have you seen a GI doc? It might be a good idea to get a scope down there and check things out.