What you describe reminds me of when my top ribs had raised up and gotten stuck after some really severe spasms.

I had a feeling like a tight turtleneck sweater was on all the time, was constantly pulling on neckline of my tops .
felt like I had to clear my throat all the time
just a weird pressure that would not go away

I found an advanced PT (taught PT also) for an independent evaluation and during the exam I was mentioning those symptoms - so he said "let me try something" - I said OK..
He placed his hands on my top rib on one side and held down with firm pressure, then released and stepped back to see if any change happened.
A student was assisting/observing with notes and such.
He asked her to look at how much that side had lowed compared to the other. 1/2" or 3/4' can't recall but it was a noticeable amount.
so he did the other side too and same result.

That weird tension & the throat feelings were gone and I was able to drive home without having to constantly switch hands on the wheel.

That raised top rib had been closing off /pinching things between the collarbone even more than usual.

My chiro had resolved the severe spasms and helped with misalignments & muscle pain and many symptoms, he didn't realize about the raised top rib.
After telling him about the PT eval and what happened , chiro always checks the top rib now.
He only has to adjust it once in awhile and I haven't had any of those severe spasms since. I know what set them off and don't temp it anymore.

With the plate /screws and such it's hard to say if it might apply for you or if it is something else causing that pressure & feelings for you.

Have you had any really good /expert PT to feel the tissues and see what they think?
some time the hands will tell more than imaging - if the person is really good.
How long ago did the accident happen? weeks, months , years?
You don't have to give specific date , just wondering how far along you are healing wise.

PS, after reading your second post I can add a few more things.

Look in our useful sticky threads up at the top of our TOS forum there/s a dr& PT thread also.
in post # 1 of the useful sticky thread look at the alternative therapies, the chiropractic info
I'm thinking your c1 c2 are misaligned - don't know if any injury in that area though..
possibly other spinal misalignment s since you mention lower body sx too.

MDs generally do not study the body/structures in depth like PT & DCs unless they are personally interested.

Expert DCs or PTs might be something to look into.