Welcome at HCM.
I have read details of your questions.
I very much concerned about you.
Reason for your present problem can be -
-Infection at site of surgery,within bone .This can be a low grade infection.
-Lack of complete union at site of surgery.
You should consult to your doctor & should have a x ray
done .An expert orthopedic surgeon will be able to give you final answer after looking at x ray & doing some investigations.
Hope this all will help you.
With best wishes.