Numbness/tingling of lips bottom/upper & alternating sides off/on. My doctor said not sure why. What could cause this? Could spinal arthritis/dddcause

No! Lips would not - Be affected by spinal arthritis, as the nerves supplying the face are the cranial nerves, mostly the facial (7th). Check with an internist as some conditions do cause numbness around the lips, to get investigated for it. May be a neurologist would be able to help.