Did the chiro do upper cervical adjusting? the c1 c2?
with the past concussions that might be a bit of help..but not instant, it takes time as the ongoing injuries took time to get this bad..

I went to a very good chiro for many years, he used many modes of treatment, ultrasound, IF stim, NIMMO, trigger point, top rib mobilisation, whole body posture , the upper cervical & low level laser..
Early on during my worst spasms , it took him 2 months (2x a week) to resolve the worst of my issues.
I continued seeing him for quite awhile ( monthly or every other month) until I felt I had reached my max improvement..

I will say the arms forward posture of truck /car driving is very irritating for most w/ TOS...
It won't go away or improve unless you do something and make changes...

You may end up making it a work comp claim, I don't know the comp system for MN.. you might explore that option.. privately don't announce it to anyone at work.. work comp is a pain!
Not an easy system to deal with, but the job & long hrs are a big factor.. can you apply for any other jobs in the company, with less driving postures? less hours?
I'll be blunt.... if you do continue working as you are now ... it won't be a good thing..
Others had big income jobs and pushed themselves past the point of no return.
Nerves get mad and stay mad a long time..

Poor PT can make you much worse..
It took years to get this injury and may take years to recover with the best of treatments..
You can call nearby pro sports clinics and PT places to ask about who they recommend locally for TOS.. be ware of those that say they know all about it.. most times they do not really know.. so if you haven't explored all our stickies... do that and learn as much as you can so when you see Drs/PT , DC you can tell if they are knowledgeable or not..

How did your mom do with her surgery? Everything went well?

Sorry,,, if you lurked , you have read most of this kind of info already..