I once decribed the tighness as several rubber bands stretched across my face and head - one band went across my chin, another under my chin, another across my upper lip under my nose and one across my forehead and one across the top of my head and down the sides and each wrapped itself around my ears so as I opened & closed my mouth all the rubber bands would stretch at the same time and the pain would radiate throughout. Although it can be related to tmj in my case it stemmed more from the cranial and cervical derangement and muscle dysfunction due to a messed up bite. Poor dental work attributed to a changing a bite and then my jaw deviated which then pushed the cranial and cervical alignment off. You may want to take your MRI films to a chiro - some are quite adept at reading them too - or they will take their own head and neck xrays - and let him see if any of this is due to cranial or cervical derangement or misalignment.