Day 8 - weird back pain

I was driving home last night and got a really odd sensation in my back all of the sudden, kindof like it went out on me. I was looking ahead, back straight, not in any kindof strenuous position that might bring something like this on. The pain is not severe, its moderate-mild. 5 years ago, while picking up my little boy, I tweaked my back pretty good and had to go to the hospital - it feels mildly similar. My husband was concerned that it was my liver or kidneys, but when I showed him where it was - its in the upper/middle of my back, he said it couldn't be any of my guts.

Have any of you had similar experiences, and does it sound like anything to be concerned about? I'm not too concerned, but I definately need to take it easy today and don't feel like I can do my normal activities and that bothers me a little. Could it be detox?

Anyhow, thanks for your help.
Mrs. B