Hello,
So none of the MDs suggested or thought of any PT sessions , to see if it helped at all???
The Disneyland trip & dd on shoulders, could have strained or misaligned or impinged something in that area.. Plus if you went on any active or jarring rides..
It's very possible some good PT or chiropractic care might take care of some of these concerns for you quite easily..

It is worth a try and probably better than waiting around for a dr to come up with more testing..you may not even need more tests..
Find really good PTs and/or DC.