Having an extra vertebra is common, BUT my Neurosurgeon said that it DID cause my spine to become unstable, and thus caused some herniations. So it DID make a difference in my spine. I guess there just wasn't enough room for them all.
X-rays that you had aren't enough. They don't show the discs. Discs are SOFT tissue, they aren't bone, and X-rays only show bone. You need an MRI with and without contrast material. Ask your doctor to have one done. I'm sure he will if you ask.
Get the report from the MRI -- you can get one if you ask. Then bring it here and post it. We can help you decipher it. Best of luck and God bless. Hugs, Lee