Your weight is not much but still due to belly fat u have pain. May be some deficiency. Write me on personal chat for diet counseling

First of all you should not do brisk walking or running if you have backache ..it aggravates the backache. You should strengthen your back by yoga or core exercises....once your back is strong.....than you should plan for brisk walking and running. Will be able to help you with diet if you provide me details of your daily food intake. I can just advice you to reduce tea or coffee intake, biscuits, bakery, junk food and increase your intake of fat burners like salads, fruits, sprouts, green tea without sugar or jaggery, egg whites.