What causes constant canker sores inside my mouth? could it be an internal problem or just something i am eating or using? thanks!

Its a virus: The most common form of recurring ulcerations in the mouth are called apthous ulcers. They are caused by a virus similar to the herpes simplex 1 virus. Once you have contracted this virus it is with you for life. Eruptions of oral ulcers are commonly related to a fatigued immune system. For example, being overly tired, stresses or sick , will make you more prone to outbreaks.

Many Possibilities: It could be a virus but those lesions usually appear on the lip. If inside the mouth, possible causes of apthous ulcers include citrus fruits (e.g., oranges and lemons), physical trauma, emotional stress, lack of sleep, sudden weight loss, food allergies, immune system reactions, and deficiencies in vitamin b12, iron, and folic acid.Trauma to the mouth is the most common trigger.