My wife has had lower back pain for 3 days now. Causes weakness in legs, Any Help?

After an injury in 2007 she has had pain come and go every few months. The doctors would just gave pain medication each time she went. As of late, the past 3 days, she has been having pain in her lower back, hips, legs, down to her knees. It gets to the point where she can not stand or walk. Her back is now shifted in an oddly shaped "S" and she leans when she walks. On 6/27/11 she went to the hospital again and they told her she had a UTI and did not know what was causing the pain. They didn't even check her back, just gave her a shot and also Norco which didn't take away the pain just left her on "Cloud 9", so to speak. She can not sit in any position for more then 10-15 minutes. We are here to look for possible answers and/or solutions. Thank You for your help