I got a back pain once, 1 month unable to move and then, a specialist of sport injuries told me that most of back pain problems can be solved with back work out. It was 10 years ago never had back pain since. Your problem seems more serious. I'm with you on it.

If it can help I would suggest you to try a more vertical casual style ride If you haven't decide that yet.
I would suggest you as well the easyseat active from SQLab, it is made by doctors. I have used the pro hub x2 from SQLab a more sporty easyseat saddle for more than a year and it is by far the most comfortable saddle I have ever ride on. It has its own spring effect which make it good for the back.
I wanted more speed so I've been on a more speedy saddle since at this time I realized how comfy the pro hub x2 was. I still keep it in case I decide to go back casual.
The thudbuster LT seatpost would be a good plus as well.

Hope you get better