My daughter that's is twelve and is always complaining about her body aching. she says her calf muscles and back hurt. she also can't get comfortable.?

Check feet & legs: I find many kids have limitations about their ankles & lower legs where limited ankle mobility leads to leg & back issues. The achilles tendon can be tight & may respond to stretching to the point the kids have less complaints.Your pcp, orthopedist or sports medicine person may be able to help.

Does your : Daughter have flat feet, is she overweight , does she wear high heels, poor posture , is she active? Had she had her thyroids checked ? Please get her evaluated by her pediatrician. She may be referred to specialists depending on lab results. May need to go on diet.Get her checked for diabetes too. Good luck!