Sharp pain under left breast after I ate some sugary food. I layed down and it was an awful pain that only lasted a few seconds. Now I feel hungry.

Sharp pain post eats. May be reflux with or without H Pylori , that worsens when you lie flat. Would elevate head of bed, consider OTC prevecid and or ranitidine, Could also be food intolerance , gallbladder . f/u w/ doc urgent care h pylori needs antibiotics.