H. pylori (Helicobacter pylori) is a type of bacteria that infects your stomach. It can damage the tissue in your stomach and the first part of your small intestine (the duodenum). In some cases it can also cause painful sores called peptic ulcers in your upper digestive tract.
In a hiatal hernia, part of your stomach pushes up into an opening (the hiatus) in your diaphragm. The diaphragm is the muscle between your stomach and your chest.