My friend Jake had the exact same problem last month. His desk was too high, so he lowered his chair and the pain went away in days. It's crazy how one small change can fix everything.
Jake's quick fix with the chair lowering sounds like a miracle cure for back pain. It's almost like our bodies prefer not to be twisted into pretzels all day. People spend lots of money on fancy office gadgets when the answer is right under their butt. As burns.patricia pointed out, sometimes the simplest solutions are the best. I bet half the office aches could be solved with a screwdriver and five minutes. We overthink everything until someone like Jake shows us the obvious.
Seriously, I was just reading something about how sitting position causes most of these issues. Good on @burns.patricia's friend Jake for figuring it out so fast.