Hello, I can understand your concern. The first possibility from your description of the swelling and location seems to be presence of apthous ulcer or canker sore. However, these ulcers are very painful and you are not having much pain which negates the possibility. Secondly, the location you have described has a minor sublingual salivary gland. If this gland or duct passing saliva is traumatized due to some reason, it can develop a swelling. This swelling usually hurts while eating and otherwise does not hurt. Thirdly, it could be a cyst developed in the area. Cysts are fluid filled cavities that are lined by the epithelium or a small lining of cells. Cysts are painless unless infected. However, it is very difficult reach a diagnosis until the swelling is examined. I would advise you to visit a dentist for the examination of the swelling regarding its texture, exact location, symptoms, color and size. You might have to go for blood test and biopsy. Based on the examination and test results, diagnosis can be made and management can be advised. I hope this information helps you. Thank you for choosing HealthcareMagic. Take care. Best, Dr. Viraj Shah