What should I do to heal a lower back sprain?

My senior year of high school, I sprained a (my doctor thought) ligament in my lower right back. Now, a year later, when I have to lean over or bend, it still hurts. The pain does not radiate anywhere, it is not constant; just when I move in the wrong way. I thought this should have healed by now, because think it's just a mild sprain, but no matter what I do I will always have to bend or lean everyday. Is there some way I can get this to heal? I'm extremely sick of living with this annoying pain and my future is one that will require strenuous physical activity. Thanks.