Pain in Lower Back/Upper Glute

I have a pain in my lower back /upper glute area in my left side. However, I do not know if it is an injury because the area feels better after RDL’ s. What could the issue be? Any stretches or movements you all recommend?

I can feel the pain if I stand and raise my left knee high.

I am making an appointment with a doc but, would like to know if anyone has experienced this.

Google athlean x how to fix low back pain.