It sounds like loaded hip flexion is what provokes the pain early in the day, is that correct? (You used some kinesiological terms in your post, being a coach and athlete, but let me know if you need clarification on that.)

Reading your post makes me suspect your rectus femoris is part of the issue. Is getting into a coach stretch position (hip extension with knee flexion) problematic for you?

Also, just to clarify, what specifically implicates the piriformis as the source of the issue for you?

Again, for clarification, you don’t recall anything unusual about the days leading up to the onset of your symptoms? No traumatic episode, no change in training, no grievous movement errors?

Apart from the chiro’s and MT’s, have you seen your physician? It would be good to rule out leg cancer and other non-movement-related issues.