@elsa Hi Elsa, I know that you had a microdiscectomy, but that issue can reoccur if you still have a damaged disc in place because a microdiscetomy just removes the part that was extruded. My experience with a spine problem also had expanding pain. I think you should investigate the possibility that your pain may be due to spine related changes as it has been ten years since your spine surgery. I don't know how MS would affect this. Because you describe that the symptoms change from standing to sitting and laying down, it sounds spine related to me. Your spinal cord moves and changes in these positions, and stretches when bent like when you sit, and when you lay down, the curves in your back can straighten out a bit putting on pressure in different places than when standing. You could also have some instability with movement of vertebrae slipping over another that change between laying and standing and sitting. I had spine surgery with Dr. Jeremy Fogelson in Rochester and he is excellent. Of course other specialists will have to weigh in on if they think this this is disease related or a physical spine or nerve compression issue. Here are 2 stories about Dr. Fogelson, mine and another. If you come to Mayo, all that can be accessed. Let me know if I can answer any questions. I was very impressed with my care and excellent recovery and Dr. Fogelson is a compassionate surgeon.
https://sharing.mayoclinic.org/2019/01/09/using-the-art-of-medicine-to-overcome-fear-of-surgery/
https://sharing.mayoclinic.org/2017/07/26/spinal-surgery-saves-teen-swimmers-mobility/