It could be because of stomach problem , or if you are consuming too much of spicy or outside food. You should visit a dentist to rule out any dental cause.

Poor oral hygiene and a vitamin b12 defeciency can bring about frequent ulcers. Other underlying medical conditions should be ruled out and treated accordingly.

Don't worry it happens at this age, these ulcers are stress related. Improve your diet with increased water intake, a glass of milk and fruits daily. For detailed diagnosis visit a dentist.

There is no specific treatment for mouth ulcers.. You can get only symptomatic relief..there are many factors that cause mouth ulcers like stress, vitamin B complex deficiency, Higher Antibiotics, less sleeping time etc..Try to find out which is your root cause and treat your ulcers accordingly.. It may not give you permanent relief but it will definitely cut down the frequency and severity of occurrence of mouth ulcers..

it Might be due to sharp tooth cusps in that region, plz get your oral sceaning done.