it can be due to gastro esophageal reflux disease...which causes damage of mucosa by acid reflux interns results in invasion by microorganisms and irritation by food particles which may presents with your symptoms try eating several small meals instead of three large ones whenever you can.Avoid foods that irritate your stomach, especially those that are spicy, acidic, fried or fatty.avoid coffee,tea etc.Stress may make your gastritis symptoms worse. Stress may be hard to avoid, but you can learn to cope with it. If you have trouble relaxing, consider calming activities, such as meditation, yoga etc...sleep with head raised position and have dinner atleast 2 hours before sleep..consult doctor if symptoms persists long