Hi, I wonder if your sciatic nerve is playing up and aggravating the piriformis muscle? as the nerve runs under the piriformis, or in some people, through the piriformis. I have this pain too and cannot sit down for any length of time which is SO frustrating. Unfortunately the osteopath was unable to fix it despite having the treatment Di describes above.
I think in your shoes I would probably try the injection first and take it from there.
Take care
Myrtle
