The issue here is the guys shot. If you take a look at it, it is kind of like Charles Barkley's golf swing. There is a hitch in it. This has nothing to do with range of motion and has nothing to do with thoracic outlet. He has a mental block when he actually is going up to shoot the ball. This is not a physical injury. It's also the same reason chuck knoblauch could never throw to first base after he was a gold glove second baseman for years.
What this kid needs is some time away from basketball, probably some psychoherapy, a lot of meaningless sex, and less visits to specialists.
I believe in thoracic outlet syndrome when there's a big honkin spinous process at C7 or a cervical rib, and when there's vascular issues. If it is neurogenic, then you should see some sort of EMG findings
At least we can take some solace in the fact that we order a lumbar spine MRI on fibromyalgia patients, but this kid is getting a multimillion-dollar work up without any physical injury.
I suppose I could be completely wrong about this, and I may be the talking out of my ass, but it just doesn't feel that way