Mouth ulcers and burnt feeling in the roof of my mouth? I don't think any food scratched or burned there.

Are you sure? The most common cause of ulcers on the roof of the mouth is a thermal burn from eating pizza as the cheese sticks to the tissues. Simple trauma may also lead to eruption on the palate of herpes simplex virus with blistering!
Mouth Ulcers. Mouth ulcers can be caused by minor trauma to the oral cavity. Other causes include: stress & anxiety, hormonal changes, family history, foods like chocolate, coffee, peanuts, almonds, strawberries, cheese, tomatoes, wheat flour, stopping smoking, medical conditions like crohn's, coeliac disease, iron deficiency, reactive arthritis, B12 deficiency.