I've tried foam rolling, stretching, trigger point, massage therapy, tens, belly breathing, pounding on it in frustration, etc etc. I have not tried anything bike fit related as it's an off the bike issue as well in the form of shortness of breath and tightness along my thoracic spine. Trust me - I've considered placebo effect as well and I've attempted to ride through it many times with no success. I spend LOTS of time on the trainer in erg mode in zone 2 for hours at a time. This is a great time to keep a loose upper body, practice breathing, and see how low I can keep my heart rate. When my back is acting up, however, my heart rate is invariably 10-15 bpm higher and it's pretty infuriating (not to mention uncomfortable) when my heart is racing to maintain 60-70% FTP. It makes it hard to finish some of these workouts as decoupling adds to the already high heart rate. So yeah, I've tried riding through it for days at a time. When I was riding less frequently, I might go a month or two without seeing the chiropractor. At 15-20 hours/week, it seems I need to go a couple times a month minimum. When I do - instant relief and instant drop in heart rate. No amount of trying to "feel good" or focusing on lowering my heartrate can seem to replicate it, so placebo??? I don't think so.