The easiest method: lie on your back and lift your legs up. The kidney will rise to the usual place, and the pain will subside. To reduce painful sensations the medicines with spasmolytic effect will also help the kidney health.
However, do not take a great interest in self-medication. In the absence of relief, and especially if the lower back pain is accompanied by an increase in body temperature, you need to see a doctor. You should also ask your doctor that what does a kidney stone look like?