How about chiropractic? I understand Sciatic often shows up if you have certain disks in the lumbar region out of whack? My sciatica has been painful for a full 6 weeks which is about 5 weeks longer than it ever has lasted.
If you choose to see a chiropracter...choose a GONSTEAD trained one...I see a chiro (Gonstead)...he has helped, but especially when he said Pilates would be good for my back...I did not see him for 2 years after I started Pilates...LOL. Right now we are trying to keep my bottom vertebrae from fusing...and dealing with bone spurs up and down my spine. Good luck to you.
I don't use a plumber for my electrical work.
What did your MRI show?
Lol! - I carried my coccyx pillow all over the college campus when I went back to school a few years ago and found myself sitting on those hard chairs hours every day!
Also, for me there’s no need for a thick pillow. Mine is thin like the one in the photo. A friend got a thick one and it was uncomfortable.