A chiropractor that posted on a forum in the past, used to explain some of the TOS pain/symptoms this way.
He was an expert and treated many of the Florida sports teams members.

He used a weight measurement but i can't recall the amount it was.

He said it only takes x amount of pressure/impingement/compression to cause a nerve to send out pain/symptom signals. It was a very small amount is all I can remember...