Day 11 of my juice fast: back and side hips pain - is that normal?

Hi Everyone,

I had Lichen Planus 10 years ago and my scars haven't yet disappeared. I chose to do the juice fasting and see if it can help them. I am on day 12, but since last night, my back and side hips have started paining when I lie down and put pressure on them. I guess its because of the body weight on it. I'm currently 55 kgs. I wasn't sure if this is normal or due to the weakening of my muscles. I would really appreciate it if you could give me some advise.

Thanks in advance.