Mine's still not sorted either. Some days it feels like the bottom of the hamstring, sometimes the top, sometimes the middle of the buttock, but always there somewhere and liable to get worse if I go any faster than a slow jog.
Physio said "hamstring" and gave me strengthening exercises. I'm not convinced that's the entire issue. I'm now doing those together with glute and hip flexor exercises, along with the piriformis stretches.
I reckon if I do the lot it might just help!