Positioning during the injection(s) can cause soreness afterward.

Here's a page that might explain some:

http://www.spine.org/articles/facet.cfm

You can find more by clicking on the link below:

http://www.google.com/search?hl=en&q=%22facet+joints%22

Any time I've had injections or PM procedures, it's been bilateral and multi-level.

What did the pre-op consent form (that you signed) state would be done? The form you signed will tell you what was done.

I always have to sign a form prior to any injection, etc., and I am given a copy before I am wheeled out.