Get anatomy book...or ask massage therapist. My guess is quadratus lumborum, but it is an underlying muscle but runs from last rib to pelvic top. It can get overworked often because of lazy gluteus (we sit on them all day).
https://www.mmphysiotherapy.com/...f-low-back-pain.html
I am not physio or health pro....just geezer who has had every pain thru many years of basketball, soccer, tennis, running to ironman ( will try again next year) all the while with dreaded desk job. Wished the internet was around in my younger years.
https://www.mmphysiotherapy.com/...f-low-back-pain.html
I am not physio or health pro....just geezer who has had every pain thru many years of basketball, soccer, tennis, running to ironman ( will try again next year) all the while with dreaded desk job. Wished the internet was around in my younger years.