Buy a small water melon. Eat it all while laying in a warm water in a bathtub between 2-3 o'clock in the night. You can urinate right in the water when you feel like. Adjust water temperature to the most comfortable for you.
This procedure usually helps me a lot if I have any kidney discomfort.
It is also good to drink some kidney herbs (red bilberry leaves, for example). And keep your low back dry and warm by tying pure wool cloth or scarf around your waist.
If none of the above helps, take Citrocept twice a day.