The two can without a doubt be related.

In my two previous bouts with TOS, on both the right and left side, shoulder impingement preceded the TOS. It makes sense if you think about it. Usually, a tight pec minor and weak rhomboids, lower traps will contribute towards impingement. The humeral head of the shoulder will be pulled forward out of the socket because of this. This will create less room in the thoracic outlet area. If you have extra cervical ribs (like me), you'll have even less space.

That's why I keep preaching the importance of keeping the pec minor loose, having a strong back, and keeping good posture. It's all connected.

That said, having shoulder impingement doesn't mean you're going to get TOS. It can be a key element.

KY