J.M.
I'm sorry youre having trouble with your little girl. I know what it's like to be in your situation. My son (8 months) was diagnosed with kidney stones, but we have yet to find out why he is forming them. He gets unexplainable fevers sometimes...they usually hit around 102-103 and last for a day or two. His nephrologist said that they could be due to his stones. So...to be on the safe side, make sure they check her kidneys and at least rule out the posibility of stones. (My son also had no other symptoms, his stone was found on an xray he had when they were checking him for pneumonia during one of his unexplained fevers!)
It could really be anything. I know it is very very hard not to worry about your kids but try to keep some sanity for her sake and yours. Ive learned that its best to think positive and not think about all the things it could potentially be, you'll just drive yourself crazy!
I hope this helped a little.
Good Luck and God Bless!! Keep us updated!