Child Pose gives Pain in MidBack Right Side

Hi,

I face severe sharp pain when doing child's pose. This area generally feels aggravated during activities as well sometimes, but the pain comes out on stretching.

My posture in child's pose is straight. I only used 1 arm here so that I could point to the area. This area feels like it has something tight, like a knot that needs to be loosened.

Would appreciate if anyone could guide me about what this is so that I could look up some videos online and try remedies. I've tried 2 local physios and none of them seem to understand the problem at all. They brush it away and say just do stretcAttachment 1643hes it'll be fine, but this has passively been going on for 2 years and it isn't fine.