Me, not just the lower back but also the knees, so I switched and both went away.
I went to the Flying Objects 'Transit' harness because it has a high hook, I also sail in the waves, so that's what I need.
It's been redesigned a bit, not sure if the hook is in the same place but pretty sure it is, and it's adjustable.
A pic like mine, I think it's a 2016, that hook shown is lower that where I have mine.