Honeybun: "Upshot was that the problem was in my shoulder, and after massage and ultrasound it gradually improved, probably over 3 months. Physio said my shoulder and neck were very tight. … "
It is unlikely to be trigenimal neuralgia as that stems from behind the face as I stated above. The operation to ease those symptoms is via the back of the head, the surgeon then releases the blood vessel pressing on the nerve route. It is a sudden, painful, shock - no treatment eased my symptoms but fortunately it went as sudden as it had arrived. Until I had dental treatment 2 years ago which triggered symptoms until the bruising settled.
I hope that once you have spoken to the dental surgery and explained you will feel easier. DO NOT take any valium etc. unless the surgery tell you it's OK in case intervention is required.