Quadratus lumborum spasm or other ideas to look into?

Hello, I've been dealing with lower back pain for about 4-5 years now and I'm wondering if anybody here has any thoughts on what it might be. I occasionally get intense clenching spasms in my lower right back near the spine. Muscle relaxers help. Heat maybe helps a little. It doesn't seem to coincide with some major trauma like lifting a car or something

Mri didn't show anything of note. Tried some anti seizure meds which didn't seem to do anything. Tissue scans didn't indicate anything torn. Steroid injections didn't make much difference.

Lifting my right knee to my chest is a specific problem movement when it's acting up (like putting on pants or socks) as well as generally having my arms stretched straight out or trying to pick something up at chest height at a distance (lifting from the ground at my body is easier than picking up something far away on a counter top)

My current guess is quadratus lumborum spasm? I'm going to a primary care physician next week and I'm looking for other ideas from the community on what to talk to them about. Could be potential causes to look into, or even if you have suggestions for what kind of doc to ask to refer to. I've found in the past I need to be a better self advocate of my own medical issues because several specialists in the past have just told me "huh, muscles/nerves are weird!" And left it at that...