My daughter, age 12 has been complaining of a sore knee for two weeks. She called from school this morning saying her knee is now throbbing. She has also been extremely tired, lethargic, low energy. For example, this weekend slept 10 hours Friday night and took a 1 hour nap on Saturday, and slept 11 hours Saturday night and took a 2 hour nap on Sunday. Does not have the energy to do anything except lay around the house. Not her normal perky self. Called her pediatrician and scheduled an appt. for later this week. Could this be thryoid related? I should add, she has not injured her knee or played any sports since complaining of her knee pain .