Your mouth is the first stop in your digestive system. Inflammation or disease in your stomach, intestines and related organs can cause oral pain, headaches, ulcerations and make you feel generally awful. Many times, evidence of these digestive problems will show up first in your mouth. If your gall bladder or appendix starts to become inflamed, the first signs may include headaches, ulcers in your mouth or a change in how things taste. Eliminate fried and fatty foods, make sure you eat a lot of fiber, including mostly fruits and vegetables, and drink a lot of water. If your problems persist, consider being evaluated by a Gastroenterology specialist.