Did your doctor not give you ANY suggestions? Change doctors! You don't need someone to joke about your child's health! I personally use an over the counter rub-Tiger balm to help relax muscles...if your child isn't talking to you, FIND someone she can talk to therapist-(insurance)..at the school, friends mom, neighbor, G-ma...A six year old should not be stressed out.
Have you ever slept with your child? Will she allow it? Do you read bed time stories? If "yes" to any of this, stay in the room with her until she falls asleep, possibly go back and lay with her in case she does wake up, maybe she will talk to you then about what a dream was about or what is bothering her, at least you will be there to comfort her...Stay positive! Good Luck!