Stomach ulcers are sores that develop in the lining of the stomach or duodenum, which is the first part of the small intestine. Stomach ulcers are also known as peptic ulcers, gastric ulcers, or duodenal ulcers. If a person has an ulcer, they may feel a burning sensation in their stomach. This burning sensation often. Lasts a few minutes or several hours. Eases after taking antacids or stopping food intake. Starts in the middle of the night or during meals. 6 ways to relieve stomach ulcers at home natural remedies.