If the glutes do not work, the other muscles including piriformis take over and get tight. I had this last year took a while to get sussed out.
Stretch hip flexors and hamstrings. Also quads and calves.
Crab and clamshells exercise to get glutes working. band round legs do monster walk.
Foam roller ITB and whole of legs and glutes.
Get checked out by any good osteopath/SMT/physio.