Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine you and obtain a history, I can not tell you what the exact cause of your symptoms is. However I will try to provide you with some useful information.
With paralysis of both sides of the face, what is termed bilateral facial palsy, with systemic symptoms such as body aching, fatigue, etc, there are certain infections that would need to be checked for. These include HIV, Lyme disease, and syphilis (please understand I am not trying to imply I think you have one of these conditions, but only that these infections can cause paralysis of both sides of the face). With a normal MRI of the brain, it is reassuring there is not something like a tumor or vascular malformation, but if the MRI was not done with contrast (dye) then some things may have been missed. For example, there is one condition called sarcoidosis, which is an immune-mediated problem, that can cause bilateral facial palsy. A lumbar puncture may also be necessary to investigate other causes.
Continued follow-up with your physician is recommended.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.