I was watching a live stage performance on Saturday when an actor rushed onto the stage as part of the performance. Though his speed was deliberate, the slippery stage wasn't. The previous scene had included some drinking, and some liquid had accidentally splashed onto the stage. As he reached mid-stage the actor’s right foot slipped and shot out from under him. He instantly regained his balance as many of us do when we slip like that, and carried on without hesitation. Professional to the last, his face showed no recognition of the jarring his lower back had just suffered, but I knew that he must have felt it. I also thought to myself that he would notice it more later on, either that evening or over the next few days.
The point is that slips like that happen to many of us, and more often than not they don't hurt at the time. They tug or pinch, but don't hurt. It happened to me recently, and I felt the tug at the base of my back, just above my pelvis. I immediately massaged the affected muscle, settling it down and preventing it from coming back to haunt me later. I’ve had many clients who weren't so lucky, and have suffered years of recurring or constant pain in their lower back or hips following just such a slip. One client had suffered for some seven years following a slip and fall on ice. She was in so much pain that it had reduced her ability to do most active things, including walking further than the local shops.
If your foot slips away from under you as you're walking and you feel a tug or pinching in your lower back, rub the affected area immediately for a good few minutes. With any luck this will ease the problem away. However, if you continue to feel soreness, pinching or tugging, or stiffness then get it checked out. It may be a muscle in spasm, and it can stay that way for a very long time, affecting your everyday life.
The sooner you sort it out, the easier and faster it will be.