I have so much canker sore in my mouth ?

Canker sores: are not pleasant and can be very painful. Canker sore is the most common oral lesions. Individual ulcers typically last 1-2 weeks. The condition is idiopathic (the cause is not known) and recurrent aphthous ulcers are usually self-limiting. Your dentist may prescribe an antimicrobial mouth rinse corticosteroid ointment to control the pain and irritation.

Acidic foods/drinks: The reaction of people to acidic foods is very variable. Some people are just more susceptible to reactions to acidic foods and drinks, like orange juice, pineapple juice, fruits, tomatoes, and others. Stress and anxiety also create problems sometimes. As far as i know, prevention is difficult except for keeping track of what you eat and when you get the sores.