Question about neck weakness and discomfort


My 19 year old daughter has a 6mm chiari. We are in the process of discovery if this is her problem or if she has low spinal fluid pressure. My question is, she has neck weakness and discomfort to the point where she is now wearing a cervical collar to help support her head. She feel like she is unable to hold her head up all day. she is a college student and if she does not have the collar on, she physically holds her head up with her hand during class. None of the doctors she has seen has addressed this issue and it only seems to be getting worse. Thanks for any insight or suggestions.

Concerned mom