Because jogging is hard! I thought.
But it turns out, if I do it really, really slowly, with the only intention being to shake my body, jogging is not hard. In fact, I'm amazed at how easy jogging is. Granted, most of the other joggers on the trails whiz past me. I'm just a few paces faster than the fast-walkers; however, if I'm only doing it to shake my body, speed matters not a jot.
And it makes me feel good. And the pain that was hurting me -- completely wracked back -- has alleviated. I shook it out of me.