I haven't been on curezone for a long time so it's a coincidence I saw this post.
When I first started fasting the leg pain would start within 12 hours of fasting. As I have gotten healthier over the years it takes longer for the leg pain to start and it is less severe.
However, when I fast the pain is still there and spreads over my entire body over a 3 or 4 day period where my muscles freeze completely and I have to stop.
My muscles ache every day (a flu-type ache) so I figure if I can find out what causes the pain when I fast, I can cure the daily pain that I have. It could be anything from hormones to acidity to toxins. Hopefully one day I will figure it out.
Good luck with your fasting efforts. The healthier you are before the fast, the more successful your fast will be.