Omeprazole is no longer working. no matter what i eat, not long after i feel a burning in my chest. how likely is this to be a hiatal hernia?

Some possibilities: ...There are lots of diseases of the stomach that can result in dyspepsia or pyrosis. These can be categorized as: problems with inflammation (e.g. Ulcers), with infection (e.g. H.Pylori or parasites), with motility (examples: gastroparesis, gastric outlet obstruction), with secretion (hyper or hypo-acidity), infiltrative (lymphoma, cancer), blood flow (gastropathies), functional dyspepsias, etc.