Mouth pain when eating may be caused by local irritating factors, having lipitis, ulcers, mucosal fibrosis and other diseases, etc. It is recommended to go to the hospital for timely examination and treatment. 1. If there are residual crowns, sharp tooth tips or restorations rubbing the mucous membranes in the mouth, etc., which cause pain in the mouth when eating. 2. A mouth that is chapped, eroded, or other lipitis conditions will cause the mouth to ache when eating, especially when touching the lips. 3. If you have ulcers in your mouth, you will feel pain, and eating food that touches the ulcers will cause pain, especially when you eat spicy and irritating food. 4. Smoking, chewing betel nut history may appear mucosal fibrosis, mucosal fibrosis will have eating pain, burning sensation.