Will insurance cover butt reductions if it causes chronic back pain?

Hi
Thanks for your question and sorry you're having this issue.
Buttock size is typically not considered a medical cause back pain. I therefore doubt any insurance will cover any buttock surgery for that reason. A back injury, weak core muscles or being overweight may contribute to back pain. You should consider having your back evaluated to be sure you don't have a problem besides scoliosis that can be addressed. 
If you do want a reduced buttock size liposuction may be employed to achieve this - Vaser or HD Lipo may be used for the skin tightening effect to also improve the gluteal appearance and contour.
I hope this helps....

If you have scoliosis, you can expect your insurance to cover the cost of straightening your spine.    But insurance will never cover an elective aesthetic procedure such as a liposuction or removal of extra skin/fat from a buttocks!