I tried a number of solutions to sitting back pain, and the one that's worked the best is a $20 cylindrical pillow that attaches to my crappy office chair with

I tried a number of solutions to sitting back pain, and the one that's worked the best is a $20 cylindrical pillow that attaches to my crappy office chair with an elastic band. It makes sitting in a slouching position subtly awkward and subtly encourages me to tuck my tail and sit up, as recommended in this article.