So my Lumbar spine has a mild scoliosis convex to the right, based on the x-ray I just got. Definitely has resulted in some asymmetries over time. On the bike (hooked up to the trainer) my right hip is higher than the left, and the left shoulder appears lower than the right shoulder, with a general lean to the left (as viewed from the back). Yet I clearly put more pressure on the right aerobar pad and end up pulling the handlebars to the left (there is a window to the left that I look out of sometimes, but generally I stare straight ahead at my laptop on a small table directly in front).

I just remembered that when I last got a serious bike fitting - 2 years ago - the bike fitter (who is also a PT) actually raised my left aerobar pad 5 mm, because that corrected or at least significantly reduced the spine curve when I ride. I think I discarded that change after a bit without giving it a real chance. I think going back to that would really help, actually. Does anyone else have one pad a bit higher than the other?

It's good to hear that it's not just some wild theory of mine that the fixed indoor riding position has exacerbated back issues related to my crooked lumbar spine. I'm looking forward to getting outside soon. As someone else has noted, I also have R/L power imbalances - typically around 55/45 R/L outdoors (don't have indoor data but I'd guess it's worse), so while outdoor riding will likely help with my back issues, it doesn't get me all the way there. The aerobar pad height difference might in combination with more outdoor riding.