I got growling/hunger pain in stomach, somtimes, just a few hrs after eating, constant upper discomfort, and bloating when when full. what could cause?

A few things: Including gastritis/ulcers (acid produced when food is ingested); a mass close to stomach (vs lower, in colon); gallstones; intermittent/partial or early intestinal obstruction; pancreatitis (inflammation of pancreas, which secretes protein-eating enzymes). Try eating smaller more frequent meals, and see your doctor. May need a gastroenterologist for a scope (egd=esophagoduodenoscopy).