Also check your cleat placement - if your feet are not perfectly aligned and are being twisted slightly inwards, that can also cause pain in that area. I kept getting aggravated piriformis and the solution for me was to move my cleats outward & back a little.

Another thing I have been playing with recently is John Cobb's suggestion on the cobbcycling website to turn the nose of the saddle half-a-nose-width in one direction of the other. That has also greatly improved my ride comfort.

V.