Sialadenitis: This is an inflammation of the salivary glands, which can cause pain and swelling in the submental area. The submental gland is a salivary gland located under the chin, making sialadenitis a common cause of symptoms in this area due to its location and function.

Dental Abscess or Infection: Infections originating from the teeth or gums can spread to the submental area, causing pain and swelling. The proximity of the submental gland to the lower teeth makes it susceptible to referred pain or direct infection spread.
Lymphadenitis: Inflammation of the lymph nodes in the submental area can cause pain and swelling. This can be due to a variety of causes, including infections or autoimmune diseases.
Submental Space Infection: An infection in the submental space, which can be due to dental infections, trauma, or other causes, leading to swelling and pain in the area.

Ludwig's Angina: A severe infection of the tissues in the neck, which can cause significant swelling and pain in the submental area. It's a medical emergency due to the risk of airway obstruction.
Malignancy: Although less common, tumors (either primary or metastatic) in the submental gland or lymph nodes can cause pain and swelling. Early detection is crucial for treatment and prognosis.
Sialolithiasis: Stones in the salivary glands can cause blockage and subsequent infection or inflammation, leading to pain and swelling.

Sjögren's Syndrome: An autoimmune disorder that can affect the salivary glands, among other tissues, leading to inflammation and potential pain or swelling in the submental area.
Kimura Disease: A rare, chronic inflammatory disorder that can cause lymphadenopathy and salivary gland enlargement, potentially affecting the submental area.
Granulomatosis with Polyangiitis (formerly known as Wegener's Granulomatosis): A rare autoimmune disorder that can affect various parts of the body, including the salivary glands, leading to inflammation and potential pain or swelling.