Pain caused by the kidneys is typically felt in the flank area, which is in the back, just at the lower edge of the ribs on either side of the spine.
It is rare for the kidneys to cause dull, aching pain. People sometimes equate back pain with kidney pain, but dull aching pain in the back -- especially the lower back or the middle of the back -- is usually due to muscles, ligaments, or even vertebrae and disks in the spinal column.
The kidney pain can be caused by kidney stones, urinary tract infection and many other abnormalities.These can be easily diagnosed by urine examination.
So I advice you to first have a complete urine examination to rule out any pathology in kidney & consult your doctor for treatment accordinglly.
Hope this helped.