There could be lots of reasons and one of them could be because of failed back surgery. Have you had any recent tests or seen any doctors to find out why you have the continued pain?
If you have degeneration going on....one probably will experience some pain. As we age, our spinal discs break down and you lose fluid in your discs. This makes the discs less flexible and thinner. This may cause the disc to break up/tear.
You are only going to be able to see this on an MRI, CT Scan, or mylegram.