Posted by Dr. Alison. Tweet. Painful gums may be caused by local gum or mouth disease, injury, or a manifestation of other more generalized conditions. Although gum disease is a very common cause of gum pain, it is often a late symptom of gingivitis. Bleeding and/or swollen gums are more likely to precede gum pain. For this reason, even transient or mild gum pain should be investigated as soon as possible so that the cause can be rectified without delay.