Hi
Lets be controversial: I think the 'piriformis' muscle is the not the seat of all musculoskeletal evil and should be set free. I see many people with 'piriformis' syndrome and have stopped rubbing it many years ago as it 1.does not work (in my experience) 2.only causes the patient further pain 3. Hurts my thumbs
Look for the cause and don't blame that little muscle. Ill start the "Piriformis is innocent campaign".

Steve
Hallamshire Physiotherapy