Epigastric pain goes away when lying down or bending over

Hello! I’m 23F. My GI issues started from indigestion that comes and goes, as well as early satiety. However it worsened over the months and currently I have been experiencing epigastric pain that starts after a few bites or sips of liquid. It resembles a ball of tightness or squeezing that would die away on its own 20-30/40min depending on the amount eaten or drank… Sometimes it feels like a painful bloat but mostly it is a squeezing tight sensation.. I can’t sit up straight or stand because it tightens even more when I do so. Even after it subside I would get this overdrink fullness and nausea sensation for a while.. I have done many scans but everything is ok. No gastritis, negative H.pylori result, no SIBO, no cancer cells, no inflammation. Everything is normal. My barium swallow test also came out ok.

The weird thing is, that tightness goes away when I bend over while sitting or when I lay down on the bed. In exchange I get nausea sometimes though…

Are there anyone who has this issue and how do you deal with this? Thanks!