I Am On A Reboot For 15 Days Only Having

I am on a reboot for 15 days only having juices mainly plant food On day4 , feel good and do quite a lot of walking mainly bushwalking. I'M HAVING A pain in my thighs which is most uncomfortable when lying down standing up is better and also having a hot shower relives the pain. I don't drink a lot of water, maybe this is causing the problem. Can you help me