I forced myself to sleep on my back the entire night last night because I normally can't maintain this position for more than four hours and always switch to my stomach. But by staying on my back, I learned that the back of my neck gets numb, which probably is the reason that I switch to my stomach and have so many sleep disturbances throughout the night. Is it possible that TOS symptoms include back of the neck numbness or even just neck numbness in general when laying down for extended periods of time such as sleeping? Has anyone had TOS surgery and noticed an improvement from this?

I don't get numb when sleeping, but I get numbness all over my neck, chest and shoulders if I try to stretch the scalenes. You could be stretching the nerves when sleeping on your back.

What kind of pillow do you use?

I'm currently using a low profile foam pillow. It's the only one I can use for back sleeping and I've been through about 20 pillows over three years.

A contoured one for the neck curves, or more of a flat standard foam type?

I have best luck with the contoured style.

Same here. I have a closet full of pillows.
I ended up using an orthopedic pillow like this one: http://www.amazon.com/Core-Tri-Core-...words=core+200

I wouldn't call it very comfortable and it took some time to get used to, but anything else gives me neck pain (no numbness though).

Does TOS cause muscle tightness in the neck?

I'd say muscle tightness in the neck causes TOS. The nerves get compressed by the scalenes and possibly other muscles which is what causes symptoms in shoulders, arms, hands etc.
It is also possible that compressed nerves in turn cause muscle spasms in different places.
Prior to getting full-blown TOS symptoms I was getting bad spasms in the back of the neck. Don't know if TOS was the cause or the result of that though.

Mine does - mine is postural/repetitive motion related. Not as much now but was very bad before I found out about TOS & FWH/FWS postures, chroinc RSIs etc..

forward head & forward or hunched shoulders adds strain to the neck and upper back muscles, due to holding weight of head more foreword of the body.
When the head is aligned & balanced over the spine the bones do most of the work instead of the muscles.

Neck numbness and tingling is strange. Have you had an MRI of your cervical spine?

I sometimes sleep with a cervical collar on, I also have a memory foam travel pillow I bought at Walmart that is awesome, I use it when sleeping on my side, just tuck it in my neck for support. I sleep with memory foam pillows.

I am a terrible side sleeper. I've finally broken myself of sleeping with my hands above my head, and sleeping on my stomach.