Details provided by you are not enough for confirm diagnosis.
Are you a tobacco user ?
If yes, frequency and duration ?
Any difficulty in opening mouth or swallowing food ?
In addition to these, oral examination is needed to see any white patches or oral ulcers present.
Most probably, it seems like a case of OSMF (Oral SubMucous Fibrosis)
You should do following things.
1. Cessation of tobacco habits.
2. Avoid spicy foods.
3. Eat green and leafy vegetables and fruits, esp. foods rich in Vit. A (Carrot, orange, tomato, milk, egg)
You should either consult online or visit local dentist.
Next Steps
Visit local dentist or online consultation.
Health Tips
Do not ignore this problem and do stop tobacco habits completely (if you do have)