Thanks for posting your query.
You might be suffering from juvenile rheumatoid arthritis
I suggest you to consult an orthopaedician/ Rheumatologist
nearby for a detailed examination. You may get the X-ray of the area affected and some blood tests to reach the diagnosis under his/her guidance.
Take diet rich in Omega 3 fatty acid , complex carbohydrate
, Vit-D &calcium,fruits and vegetables.
Take low fat diet.
Drink ample of water.
Watch your weight.
Have a positive attitude.
Dr Saurabh Gupta