OP: Reading your issues, sounds like you figured a lot out about where you are now. So many I'm sure ended up with health issues from what they loved to do in their lives, job wise and fun. I know my sister did who ended up with MS and I believe in her life, it was stress of the job and also foods.

For me it probably was a lot of dancing, which I loved to do and a lot of exercise, and stress from jobs but I worked on my health as best I could thru my life. Now at 83, I can't do much but have good memories.

I've been a back sleeper for probably 11 yrs since hip replacement and I can't sleep on sides, especially hip surgery side and the other side I mess up my shoulder....so it's the back. And I do sleep good. Hope you'll get some insights here.

I'll find out in few more weeks maybe. But it makes sense. Sleeping on the side of your body most affected by TOS can prevent healing.
I've been a right side sleeper my whole life which is the side most affected by TOS.
Before I started correcting my posture in my mid forties (I'm now 71), I'd experience weakness and numbness in both hands. Both arms would get fatigued almost immediately if I tried to exercise them. I became interested in juggling and it took me a long time to learn basic juggling because my arms would get super fatigued almost immediately. Raising my arms over my head made them super tired another sign of TOS.
Since correcting my posture and using a back brace and stretching the only weakness I experience now is on my right arm. So at least no problems with my left arm and hand anymore.
But not sleeping on the side of your body most affected by TOS makes a lot of sense. I probably minimized the good of stretching, good posture, and the back brace by sleeping on the damaged nerve bundles for 7-8 hours every day.
We'll see what happens.. I would like to hear stories from people who improved or cured their TOS situation by changing their sleeping positions. I could not find any stories about that possibility on the internet. But I did see a number of admonitions about not sleeping on your TOS-affected side of the body. I hope that was the problem.

Have you found and explored our TOS forum and the TOS sticky threads?
Or our site search tool might find related posts faster.

From the symptoms you describe, it sounds like you have VTOS , a blood flow based TOS.

I have only recently joined this forum, but I am eager to seek any help possible and to help anybody else if possible. Thank you for asking.
I should like to mention one other thing people can do to relieve symptoms or related health problems and that is to eliminate trigger points.
I discovered trigger point therapy in my mid thirties almost ten years before I found out my chief problem was posture related. I was also liked to play tennis and hit the ball hard. That along with poor posture possibly help create many trigger points.
But after reading books about trigger points ( can't remember how I was alerted to them) i discovered many severe trigger points on my chest and arms. As anybody who has tried to eliminate them knows it can be very painful. to get rid of them.
I am an amateur musician who plays the guitar and other instruments requiring good breath control like the harmonica and flute. I'm not going to be appearing at Carnegie Hall any time soon, but I did and still do enjoy making noise on a variety of string and other instruments.
Before discovering trigger points I could scarcely get any breath into my harmonicas and flutes. I could barely play for more than a few minutes and poorly at that. I discovered that my intercostal (rib) muscles were peppered with trigger points many of them very painful to eliminate.
But after correcting my posture and eliminating most of the trigger points in my chest and arms I began to get may wind back and play my harmonicas and other instruments needing breath like flutes and tin whistles. (I love to play Irish folk music.) I now at 71 have far better breath control than I did in my mid thirties before I corrected my posture and eliminated many chest trigger points.
So bad posture can cause many other problems. If you have muscle problems, a number of them might be trigger-point related as well as neurologically related.

sorry. I didn't read your response correctly. It's your sister who has ms. My sympathy for her.