Hi Shae,
Welcome!
Though I don't have piriformis syndrome, for many years I watched a TV program called "Sit and Be Fit," and one exercise that was done daily was the piriformis stretch. Have you been doing that exercise? You can look it up by doing a Google search for it.
Physical therapy seems to be the best recommended treatment for this condition. Have you kept with the PT? You do really need to do the exercises regularly and accurately--keeping your form is important and often even the way you breathe matters.
Here's something about piriformis syndrome, and you'll see that there are a couple of suggested treatments for cases where PT hasn't worked:
Ask Dr. Rob about piriformis syndrome - Harvard Health