My tip would be to find a comfortable and cheep perforated office chair off of Amazon or Ebay.
It being perforated will prevent or lessen the occurance of Swamp Ass from sitting down 18h a day
And don't get one of those "gaming chairs", only tryhards use them and they're ugly and gei...
Going to a chiropractor usually only fixes symptoms, which is the pain.
Try to find the underlying reason to the problem, I had some serious back & neck pain some years ago and for me a combination of improving body core strenght (back & abs and also chest) and using a smaller (lower) pillow...