Hi, i had problems sitting for more than 20 mins, if I had to use a desktop computer, the arm symptoms started after 5 mins. At a workplacement for my rehab. the opportunity to use an ergo chair happened. i bought my own, it folds up, i take it to both my workplaces always. it was great, my capacity to sit increased many fold, the arm symptoms minimal. I wondered why1) sitting made things worse compared with standing 2) Why the sitting on this chair was better than sitting on a normal chair . i deduced that sitting placed greater pressure on the diaphragm. (and we all know how TOS sufferers chest breathe, you should really try the medication to fix the breathing) and the ergo chair (picture in one of my posts) allows you to sit without placing upward pressure on the diaphragm. RIBCAGE theory. see you later Towelhorse.