I would let her doctor know about this. It probably is nothing since you also had this as a child. My 6 year old nephew had simiar problems, but with his arms as well as his legs and is now seeing a neurologist for a diagnosis. They did some tests just last Thursday so the results aren't in, but the best thing for you to do would be to have her evaluated, especially since this can be so painful. My best to both of you.
