Sapphire,
To be clear, top scoliosis revision doctors can help with your kind of pain. You might have areas of your back that never fused, which still causes pain. Or you might have developed flat back syndrome, which can make it very painful to stand up. Both of these things can be fixed, but you need to go to a TOP doctor. Where are you located? Maybe our moderator can suggest a specialist.
Also, you are right about never being able to bend. The area where you have the rods won't ever bend. That's all going to be one solid bone. I don't think it's a good idea to even attempt sit-ups and the like. Sounds like you need a more educated physical therapist, as well.
Evelyn
age 48
80* thoracolumbar; 40* thoracic
Reduced to ~16* thoracolumbar; ~0* thoracic
Surgery 3/14/12 with Dr. Lenke in St. Louis, T4 to S1 with pelvic fixation
Broken rods 12/1/19; scheduled for revision fusion L1-L3-4 with Dr. Lenke 2/4/2020
Not "confused" anymore, but don't know how to change my username.