Hello,
Welcome at HCM.
I have read complete details of your question.
It looks from your details that you had previous
injury to your leg.Most probable reason for your present
back pain is taking rest for long time.This had lead to decreased power in your back muscles.
At present you should do following to have relief in this-
-At least have a x ray of your back ,so that you may know if there are early changes of
arthritis at spine.This may be there due to increased load over your spine.
-Take a good
analgesic like advil or aleeve,These are OTC medicines.
-Do warm fomentation over your back.
-Take help of a good physiotherapist.He may apply some modalities like
ultrasonic therapy,infra red therapy,,galvanic therapy for relief.
-Learn some exercises to strengthen your back ,like-
http://orthoperson.blogspot.in/
Hope this all will help you.
With best wishes.