The exact cause of canker sores is not known for certain, but stomach pain could be related. Some experts believe that immune system problems, bacteria or viruses may be involved. Canker sores are not contagious, but can return frequently. You may have one or several. These types of sores usually heal on their own within a week or two.
A Answers (2)
American Dental Association answered
Bill Salt, MD, Gastroenterology, answered
Not directly, but abdominal pain may be an indirect "cause" of or be associated with canker sores.
Canker sores are small painful sores (aphthous ulcers) that occur in the mouth, which tend to come and go several times a year and last for several days.
The cause of canker sores is currently unknown, but they can run in families (genetic predisposition) and are probably related to the defense (immune) system of the body. They can be triggered by either physical stress (such as dental work), psychological stress and emotional upset, or by flare up of certain associated conditions and diseases which involve the immune system.
So the stress of having any painful abdominal condition could activate or "cause" canker sores indirectly. Also, at least two uncomfortable and/or painful abdominal diseases can be associated with canker sores: Crohn's disease, an inflammatory condition of the digestive tract, and celiac sprue (celiac disease, or gluten sensitive enteropathy).