Tailbone and sacrum pain

I have also posted questions about ongoing nerve pain after lumbar laminectomy. While the nerve pain is awful, it pales in comparison to the tailbone/sacrum pain I still have 4 weeks post laminectomy of l4-l5 due to spinal stenosis.

My surgeon had felt this would ho away after surgery as he felt it was likely due to inflamed nerves from the stenosis. It was completely gone for 4-5 days post surgery, but about day 6 it, along with other symptoms, started coming back. Although it is not quite as bad as before surgery, it is quite debilitating.

The symptoms range from sharp burning pain and spasms to the left, right and top of my butt crack. I have tried oral steroids, OTC pain relievers, all sorts of stretches and just started PT. None of which seem to be helping at all.

I have seen a pain management doc, who is recommending a caudal injection in the tailbone area. Which made sense at the time and I would have already had it, but my insurance has denied it.

In the meantime my surgeon ordered an MRI of that area. He said the sacrum and coccyx looked ok, but he saw degenerative changes in my SI joint. He is suggesting an SI Joint injection.

I am going to have one of these injections even if I have to pay for them myself (min $2500).

So here are my questions.

1. Has anyone experienced these symptoms before?
2. If so, how was it treated?
3. Has anyone had either of these injections? If so, what were the results?

I really appreciate any input anyone can provide. I am in a lot of pain and confused about my next step.

Thanks in advance!