a community of practitioners
Ahhhhh...is it true that 'massage therapists' cannot 'diagnose? If that is the case then I would 'assess' for coccygeal displacement. Massage of the glutes is hardly worth just 'deep tissue'. What tissue? Suggest revision of the ligaments of the pelvic bowl.
Piriformis treatment for sciatic pain is only beneficial if the pain is actually sciatic Nv in origin. A fall and Mm guarding may have affected piriformis or any other Mm but surely subsequent treatment should have ameliorated.
I would just try stacking vectors looking for positions of ease a'la strain/counterstrain.
Continual stretching maybe be counterproductive, and in fact may exacerbate, what could already be a 'false' pain signal.