hi there, i think you should eat more fat. low carb diets should be 75% fat. an underappreciated fact. you need some heavy cream and butter. lower back pain and leg pain point to magnesium deficiency - http://www.krispin.com/magnes.html#Deficiency this will tell you what kind to get. once you get more fat calories into you you should stop getting harsh pain, though. getting the fat is the most important thing you need to do. imho.

you may not be losing weight because you're actually eating too much protein. or you may have some thyroid issue.

there's lots to learn about LC.