@junebug I recently read an informative article from another site about piriformis syndrome I will attach here : http://bit.ly/2pHeHuj
I certainly understand your reluctance in getting an epidural. I have had several in my cervical spine due to stenosis and disc bulge. I will only have them done by a specialist, usually an anesthesiologist, under a fluro scope. That way the doctor sees exactly where the catheter is positioned. As I recall, it wasn't until my third injection until I felt significant relief. I hope you get some relief with the piriformis injection.