There are three possibilities that come to mind regarding your situation. The first is that despite all test indications, it’s possible your pain just wasn’t coming from the facet joints. You may have had a false positive test response.
There are nerve endings in many of the tissues of the spine. It isn’t always possible to tell whether the pain is coming from the discs, joints, ligaments, or muscles.
Second, it’s possible you did have inflammation in and around the facet joint. A steroid injection seems to help many, but not all, patients with this problem. Scientists aren’t sure why this happens, yet.
And finally, studies show that people with facet joint degeneration often have more than one level involved. If you only have one level injected, the source of the pain hasn’t been completely eradicated. You may need more than one level injected.
Don’t give up on finding the help you need. Sometimes it takes more than one injection to do the trick. Even a failed response to treatment offers some helpful information to your doctor. Make a follow-up appointment and find out what other treatment options are still left open to you.