post-root canal pain

I had a root canal about 2.5 months ago. After the sessions were completed, I had continuing intermittent pain in the upper right jaw, where the procedure was done. I returned to the dentist- he filed down the crown a little, took more x-rays, started me on still another set of antibiotics - nothing changed. I went to my physical therapist, who believed that this pain was trigger point-related, due to excessive stretching of the temporalis and masseter muscles during the procedures causing referred pain to that area. He has been doing weekly trigger point manual therapy on my mouth for several week, as well as having me pinch the masseter muscles all along the ridge daily. It seems to help for awhile. but the pain returns- intermittently in frequency and severity. HE would be glad to continue his work on my mouth, but I am wondering if it is significant that I still have the daily pain. He suggested maybe going to a dentist for 3D tomography of the skull for differential diagnosis as to whether this is dental or trigger point muscle etiology. Ant experience in this matter?