yeah, I'm not even remotely suggesting that that's what she has, but it's worth mentioning at least since sometimes doctors don't think of those kinds of things since it's not within their specialty.
Well, there's debate over whether or not EDS (the hypermobility side) is the same as Joint Hypermobility Syndrome, so it could be the former but so far doctors have considered it to be the latter. EDS is caused by weak collagen however whereas Hypermobility Syndrome is just taken as being hypermobile and it causing pain. But there is no test to actually distinguish between the two it seems.
Hypermobility Syndrome at the same time though can be a cause of EDS or Marfan Syndrome, or even brittle bone disease.
There are a lot of diseases in this area all with the same symptoms.