Yes, it is very normal and common to get lower back pain during this challenge. Because the kidneys are one of the main detox organs once they start filtering more the structures in the lower back begin to change and transform which can lead to temporary weakness. When there is lower back pain, it is a sign that you need to rest more as the structures in the lower back don’t have the strength to support your spine.
Lower back pain can also be caused by binge eating as the local blood supply is going to the intestines to digest the heavy load of food nutrients so make sure your meals are small and reasonable in quantity. Remember, quality is key.
If lower back pain is experienced during a dry fast then your kidneys are taking strain. In that case break your fast with a small glass of citrus juice or fresh concentrated lemon water.