Does this pop feel like a muscle pulling apart?

I had something similar it was a ruptured cyst. It put me on my knees with ungodly pain. I only experienced one pop though and not every time I got my period. I'm not a doctor so my advice would be to check in with a gyno just to be safe. Cyst or not it's sounds really painful I'm sorry you're going through that. I hope you figure it out and resolve it quickly so the pain resides!

Sometimes through hips and knees