What Causes Numbness And Pain In Back With History Of Having A Surgery?

I was wondering if a back injury to my lumbar spine in 2001 could be causing a more serious problem now. A friend jummped on back unexpectedly and I felt the most horrific pain. It has always bothered me and has been numb in that area. I had an emergency lumbar MRI and won't get the results until Monday and just trying to make sense of my current situation,Thank you!