I have back pain but i want to do any test where doctor can tell me exact problem, so tell mi which test i should do?

Depends: History of your pain and the physical findings and your age help determine which tests should be done.

It depends: Back pain can be due to many causes. Determination of specific test depends on the history related to pain, its nature and behavior, response to motion or lack of it, radiation to what other parts of your body, what relieves or aggravates it, etc. Other non-pain history can be helpful such as cancer, trauma, etc. Physical exam is needed. Overall, you need to be evaluated by a physician.