Lynn
I can't say this for sure, but if your little girl is 4-6 years old, she might be having old-fashioned growing pains. My son at that age suffered as well, crying out in pain in his sleep. He would do this intermittently, and the pain seemed focused on his knees and his lower legs. A co-worker of mine said her daughter likewise suffered pain in her knees at that age, with no other symptoms. I am happy to report that both our children are now well and happy...and growing!