@dgarris3 Your first statement actually sounds a bit like myself:
"I am a 53 yr old female who has been experiencing constant movement and instability in my left side from my neck to my left hip. I also get a lot of heaviness in my shoulders. This makes it very difficult to walk or even sit up for very long."

and because you talked about consults with spine specialists, it may be worth looking at the possibility of something like thoracic outlet syndrome which is most often missed and misdiagnosed by doctors.

I believe that patients with spine injuries like a whiplash may have more instances of TOS because TOS can be caused at the same time a spine injury happens. It does cause heaviness and fatigue in the shoulders and arms, and compresses the blood and nerve supply in the shoulder in various places. I have TOS that was misdiagnosed for a few years, and my hands used to turn blue and purple and get cold because circulation was compromised.

This is something that a neurologist should consider, but if you have an over whelming amount of medical data for a doctor to digest, they can easily pursue a alternate path. Sometimes things need to be excluded. TOS can be diagnosed by measuring altered blood flow with various positions of raising the arms. I have had Doppler studies that showed this, and doctors take my pulse either in the wrist or listen in my neck, then raise my arms and have me turn my head, and it stops my pulse completely. This happens because of muscle tightness or injury/scar tissue in various places between the rib cage and collar bone area where the entire bundle (called the brachial plexus) passes through on the way to the arms.

At Mayo, they actually put tiny blood pressure cuffs on my fingers and measured change in blood pressure there with raising my arms. The best treatment of TOS is most often physical therapy. Since you described bulging spinal discs, if you were describing a cervical disc in your neck, then I would ask if you have had an event like a whiplash or other injury that affected your neck?

My pattern is what you describe. My neck is tighter on the left side, and the tightness pulls from my neck through my rib cage to my pelvis and actually pulls the left side forward throwing my pelvis out of whack. That causes the left side of my lower back to ache (telling me this has happened), and then I see my physical therapist or I do some things she showed me on how to get my pelvis leveled out. That side of my body is just tighter, and I work on stretching it out to keep it aligned and reduce any pain. If my pelvis is really off, I get easily fatigued with walking and low back pain. My rib cage doesn't move as much on that side either, so I work to loosen that.

You may be interested in a couple of links, first a great article that describes TOS and why it is hard to diagnose, and the second our discussion on myofascial release which is what my therapist does to treat my TOS and it works. It is something I need to keep working on so I don't allow my body to tighten up again. The key is getting a therapist trained in the John Barnes methods of MFR. There is a provider search on http://mfrtherapists.com/
https://mskneurology.com/how-truly-treat-thoracic-outlet-syndrome/
Myofascial Release Therapy (MFR) for treating compression and pain: https://connect.mayoclinic.org/discussion/myofascial-release-therapy-mfr-for-treating-compression-and-pain/

The great thing about MFR is that you don't need to know exactly what is wrong to be treated. Many problems occur from overly tight muscle and fascia, and loosening that up allows better body movement and re-hydration of tissues as well as possibly releasing entrapped nerves by loosening up what may be compressing them.

Have any of your doctors suggested or tested for possible Thoracic Outlet Syndrome? If you find a good physical therapist, they may be able to provide some answers.