Please see Isaiah’s response to this post. Very encouraging!
I am in the same boat! Perhaps together we can keep it from sinking 
My reply will not be as awesome as Isaiah’s, she really knows her stuff!!!
Edit: From the other responses, I concur your styloid processes are long. Keep looking for help!
I do have some additional feedback. ( I have a medical and legal background, however I am not a physician. I studied neurobiology and behavior and neuroscience. I worked as a clinical trials monitor for pharmaceutical studies. I also studied fMRIs, which does not help here. This was years ago! Brief stint in law school. I ended up assessing injuries from automobile accidents. My credentials are mostly irrelevant, except I now spend loads of time researching.)
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I also have overlapping symptoms, made worse with a fall this January from a loft, where I fell on my head, the majority of the impact was directly on my left temple/upper rear cheek bone, and the left TMJ joint.
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I also have a narrow airway/underdeveloped jaw, my original diagnosis/plan was to have an appliance to expand my upper palate.
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I see you were diagnosed with moderate sleep apnea. Most doctors automatically say jaw clenching is a result of sleep apnea.
[This is true, but if you are clenching your jaw 24/7, like me, and have the 24/7 appliance (is it a lower appliance? That is very important). Do not stop your CPAP, your diagnosis might very well be accurate! Sleep Apnea is severely under diagnosed.]
Sooo…
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That being said, you have compression on your jugulars. You have a small airway. The compression might be a contributing factor for the sleep apnea.
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Has anyone examined your Sternocleidomastoid (SCM) muscles. Jaw clenching—-> tight SCM—>>> many Symptoms you describe. Please note this link is a really brief overview, I do not recommend trying any exercises without seeing a doctor. I tried, and Whoa Nellie! Pain pain pain!
I have a hypertonic (frozen) left SCM, and 4cm elongated styloid processes. Before I discovered the elongated styloid processes, I was attending Physical Therapy (Postural Restoration). It didn’t really help, but I was not the best patient. 
I stopped PT as I do not want to screw up the styloid process (no idea if that can happen).
As for the trigeminal nerve pain, the chewing and talking problems you describe do fit. A trigeminal nerve block is not scary. A neurologist simply puts something up your nose, no pain, takes a few minutes.
I had this nerve block, unfortunately it didn’t help with chewing or talking. I hope it will benefit you.
If it doesn’t, do not despair. There are tons of cranial nerves, even within the trigeminal nerves, that can also contribute.
I look forward to seeing your updates, it gives me hope!
(I hope I did not violate any rules in this post) I have no affiliation with Healthline. I would not make conclusions based on their information)