Agreed, that's how it felt for me, in fact now if I start to feel any tension in my back I go for a run to get rid of it! Which builds more evidence each time.
The last challenge for me was running. I was now totally pain free except when I ran. As soon as I set off my back would tense, the pain would seize hold around my glutes and would stop me dead within minutes. I knew that I would then be hobbling for a week. I had to clear this last barrier...