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Back pain can be due to various reasons as improper posture,disease or injury to the nerves,spine and muscles or other causes as due to abnormality in the abdomen,chest and kidney.
The possibility of kidney issues as stones can be suspected as it does cause radiating pain to the back.You require a USG scan,urine test and blood tests to rule out the exact cause and diagnosis.
Kindly visit a Physician for physical examination.Drink lots of water.
Take care!