... recently or fell or hit my back on anything. But the lower section feels as if it was hit as hard as someone can swing a baseball bat at it and its felt like that for a week and I also have major pain in my upper thighs on both sides. It hurts to bend my bank, sit down quickly, move my legs too quickly. Any Idea what this may be? Could it be possibly just a bad sprain? Just maybe an unlucky sprain?