T.J.
Does your son get enough calcium? When I was little, I remember always having sore legs. I took Silica and a mineral supplement. Maybe you could try a good liquid calcium for him, but make sure it has calcium lactate or calcium citrate in it, those are the good kinds of calcium. He will probably like the taste of it, especially if it's something he needs. You can put it in juice and he will probably like the taste of it,or blend some up in the blender with apple juice and a banana or frozen berries, like a smoothie. You could try that for a week or so and see if the pains go away. You could also massage his legs with olive oil or lotion. But I would definitely try some calcium. Good luck.