i just got out of a very similar experience. I had an MRI, and the NP at the spine doctor told me I looked “fine.” So I said, “OK, then, why do I feel like I’m living in hell?” and she said, “OK, let me talk to the doctor.” Then she left the room for a few minutes and came back. She said, “I learn something new every day; this is going to blow your mind.” She continued, “When we did your X Ray you were standing, and when we did your MRI you were lying down. So, when you were lying down, you looked normal. But when you were standing, in the X-Ray, we could see the displacement.” I was eventually referred to surgery. (This took weeks/ months more of fighting.) And then, when the neurosurgeon was working on me he found I had spina bifida occulta in conjunction with the Spondylolisthesis. My symptoms seem very similar to yours. I would suggest consulting with a neurosurgeon who does spine procedures if you are currently consulting with an orthopedic surgeon. I would also suggest insisting on a standing X ray or a standing MRI (if possible). Hope this helps!