@lineage In response to your questions... epidural spine injections are done outside the dura. They are not injected into the spinal canal. That would run a high risk of damage to the spinal cord and paralysis.

With my early symptoms, I could turn the pain on or off in my ankle by turning my head. My bone spurs were actively growing and doubled in mass in 9 months time that I could see on MRIs, and by that time, there was no fluid space at all around my spinal cord at the C5/6 level, and the disc had collapsed half of it's height. I got to a point where I could not turn off the pain anymore, but changing body position changed where the pain was felt, so when it turned off one area, another body part stepped in to complain. There was variety with numbness and tingling, and later, sharp stabbing pains or electrical pain. Those are nerve compressions. I also had overactive reflexes in my arms and legs, but later as I lost muscle to atrophy, that also faded. When I had nerve conduction and EMG testing, I didn't feel pain in the damaged areas. I did not have compression of the nerve roots, but because of the loss of height of the disc, if I side bent my neck, it touched those nerve roots and sent strong pain down my arms. I started wearing a microwaveable bead filled neck wrap and tying that with a scarf to keep my neck position straight. Bending and twisting would bring on muscle spasms of the cervical spinal muscles, and that would cause an increase in pains in my body. My C1 through C4 would get twisted independently or tilted, and this started bringing on vertigo bad enough that on one occasion, I fell backward against a door. My therapist realigned things, and I was OK again. I also have thoracic outlet syndrome which causes my neck and chest to be tight, with greater symptoms on my left side which was involved in the twisting muscle spasms. This also causes left side tightness that affects my pelvic alignment, and I work on that in physical therapy. Since my spine surgery, that has calmed down. I do still have TOS and work on that with fascial stretching. Spinal cord compression isn't necessarily predictable as to where the pain will be generated, and it can change location with the cord changes its position within the spinal canal. If you also have compression of nerve roots, those cause predictable pain that can be anywhere along the nerve path. This is diagrammed on dermatome maps where the surface of the body is mapped to the nerve roots. The spinal cord is highly mapped too, but you don't know what area will get touched by a spine problem.

I think your spine injection has caused some of your symptoms, and may improve as time goes on. It is probably similar to the problem I had caused by the injection, and that did resolve itself with a lot of improvement after 6 weeks. There probably are several things contributing to the problems. With funicular pain, it seems to be when the spinal cord in touched in 2 places at the same time that causes the referred pain. One site would be the cervical compression and the other might be related to the injection or the cyst you mentioned unless there is other spine pathology. You said they didn't find problems beyond your past surgeries. You mentioned 2 lumbar/sacral spine surgeries, and those will have created scar tissue from the surgical path in the fascia. I do myofascial release therapy with my PT to work on this. My pattern of left side tightness is a tightness in the fascial web and it also tends to pull my left pelvis forward or twist the alignment, and I have felt that tension from the connection of my neck and jaw all the way to my ankle. Sometimes the overly tight side beats up on the other side of the body because muscles work in opposition. This may be able to explain why you have pain on the opposite side of your body. It could also happen from rotation of a vertebrae changing pelvis alignment. I had that happen when my sciatic pain switched sides after my whiplash years ago. Tight fascia will pull muscles and bones out of correct alignment and function and can compress the very small spaces where nerves travel in the body. A lot of doctors don't understand MFR work and the properties of the living fascial tissue that changes between solid and semi liquid and the fascia also conducts electricity. In med school, they work on cadavers and the fascia no longer has the ability to slide and reshape itself. If you had an evaluation with an expert level MFR physical therapist, you may get some clues to where your pain is coming from in your body (and not related to the spine). I have made a lot of progress with MFR and started a discussion to collect the details and information. This may help and you won't know unless your try it. You don't always need to know the exact cause of a problem to do this. The therapist can feel the pathway of tightness with their hands. There is a provider search on the MFR website.

You might want to wait it out to see if the adverse effects of the injection wear off. Right now, it is causing confusion in locating the exact problem and pain source. If that goes away with MFR therapy and time, you can check it off the list, and it won't be a deterrent to getting a surgeon's help. You'll still have your spine condition, but that may be more straightforward for your providers to figure out. I stopped talking about having had vertigo from the twisting muscle spasms and instead just talked about the spasms and pain. I think it was the vertigo which scared surgeon #5 out of helping me because it could have a lot of causes, one of which is a cervical spine issue. The injections work by reducing inflammation in the linings around the nerves and spinal cord and they get a bit smaller. At some point, the injections stop working when there is too much compression. FYI, on an MRI, myelopathy (spinal cord damage) shows up as a whitish or mottled area inside the spinal cord. When that happens, permanent damage is happening. Mild myelopathy does not always show on an MRI, and mine did not. My surgeon told me this. Decompression surgery is more successful if done before permanent damage sets in. Your case is complex, but don't give up hope. Research doctors now so you know where to go. If you get into an emergency surgical situation, you would be assigned to whoever is on call unless you are established as a patient with a surgeon.

Here are some links about MFR, and about pelvic or back disorders caused by alignment issues. You could have that going on in addition to the spine issues.

https://mskneurology.com/identify-treat-lumbar-plexus-compression-syndrome-lpcs/ (lots of great articles on this site)
https://www.healthline.com/health/dermatome#dermatomes-list
https://connect.mayoclinic.org/discussion/myofascial-release-therapy-mfr-for-treating-compression-and-pain/