Not fun.

https://www.healthtap.com/user_questions/10651

How successful is physical therapy in the treatment of thoracic outlet syndrome?

Dr. Richard Sanders
answered:

50%
Physical_therapy
It depends on how long symptoms have been present. If less than a few months, the success rate is at least 50%. If symptoms have been present over 2 years, the success rate is less than 50%.

I am at the six year mark.