In Chinese medicine the Kidney has pride of place, as the repository of your constitutional energy - it is that part of us that we are required to take care of and not waste.
The kidneys are located just above the waist, below the ribcage at the back of the body. This place makes them vulnerable to cold. Cold slows everything down. Stiffness in the lower back is sometimes due to kidney deficiency. If your job entails a lot of standing, try to stretch and move your hips and back try not to get stiff Standing too much can deplete this energy..