Thoracic Outlet Syndrome

I have been diagnosed with Thoracic Outlet Syndrome, which is a impingement of the nerve, vein and artery bundle that goes through the thoracic area above first rib and under clavicle. I have neck pain, trap, chest, all on the left. I used to train in Karate, BJJ, and worked out 3 times a week. It has been a year since I have been doing any type of workout or physical exercise as I do not want to aggravate the pain. I have seen a chiropractor who states states that their is a misalignment, a physiotherapist who says my first rib is the cause of the "nerve pinching". I have gained about 20 pounds in the last year, all fat and even lost muscle weight. Can someone advise me of a workout that will not over strain anything in the neck area or what type of workouts I should be doing as I need to get back in shape. Any suggestions will be helpful and greatly appreciated.