Oh you should be drinking plenty of water, but I don't think that is the cause of your pain. I started having extreme pain in my lower back that would go down both my legs. I thought my back pain was from my Endometriosis, but I didn't understand why my pain would go down my legs. I also started having extreme bone pain in both my legs from my knees down. So many times I went to try and get help with no success. One doctor told me it was my anxiety and all in my head. I wish I could see that doctor now. What doctors don't get is we know our bodies and we know when something doesn't seem right. I kept searching and went through a lot of hell and finally found this awesome doctor. I had told him the pain I was having and that I thought my lower back pain was from my Endometriosis. He looked at me and said never assume anything until you know for sure. Turns out my back pain and leg pain was from my L5-S1. My lower lumbar in my spine. I have a bulging disc, degenerating disc, and swollen extrusions. How's that for it's all your anxiety. The pain had gotten to the point where I had trouble sitting, sleeping, and walking. This doctor knew something was wrong from the intitial exam. After running some tests he found the problem. I haven't worked since 2004 cause of all my health problems and I am only 25 years old. But I still believe the cause of my extreme bone pain might be another condition altogether. Usually lower back pain that radiates to the legs means a problem in the lower lumbar. I would advise you to go see a Neurologist and get an MRI. GOOD LUCK.