What is the difference btween stomach inflammation,gastritis,and ulcer? which is common n not worrisome?

Stomach ulcer: Inflammation is the reaction of your body to any insult, when it happens in the stomach it is called gastritis. There is redness and swelling happens in the mucous membrane. When there is an ulcer there is break in the mucous membrane like you see an ulcer on the skin. Irritation may progress to be an ulcer. Both can cause symptoms. Stomach ulcer has an increased risk to become cancer.

Clarification: The suffix '-itis' implies inflammation so stomach inflammation and gastritis are the same thing. Gastritis is fairly common but usually transient and although uncomfortable, usually not dangerous. Prolonged gastritis and ulcerations (erosions in the stomach lining) are concerning health issues often caused by infection with H. pylori, medications, illness or excessive alcohol use.