I'm unilateral in terms of acute symptoms, but both sides tested positive for TOS. For example, the EAST test will turn both my hands white, but the non-acute side takes longer.

When my normally non-symptomatic side starts getting some minor symptoms, which is rare, I make it a point to rest. Like stop all types of work, fix up my posture, support the arm, and watch a movie or take a nap. So far, so good.

My bad side has the depressed shoulder girdle and just the slightest of x-ray anomalies, whereas my good side does not. I expect that if I listen to my body, the good side won't get bad.

Some people in these forums have mentioned going from unilateral to bilateral, so do be careful.