https://gokhalemethod.com/ I like their desk chair, and even their lil posture-support add-on cushion, for not-their chairs.
if I may (a bit woo-woo):
can you regard the pain as a messenger? can you reframe, and allow it to be "welcomed" for that, and then, having delivered, you can then thank it for "job well done. now be gone!"?
and follow-up with a strong visualization of the post-pain relief you're going to be enjoying, "next"?
the subconscious works in f'n mysterious ways! some days, all we can do is "play along"...