I believe that you need to see a dentist that specializes in TMJ dysfunction.It sounds like the temporal muscle is the culprit and you need to find out what is causing it to go into spasm.
The dentist is an outrageous liar. The root canal AND the crown, either both or individually, could be causing this pain.
The operative statement you made was that you had never had this pain before. This is key to knowing that you did, indeed, get injured during this highly toxic procedure.
You need to get to a really good holistic dentist and get referred to a good endodontist who can perform a healthier root canal with "Endocal 10" also known as "Biocalex".
The root canal treatment alone is used with highly toxic products and it can also leave behind some root to rot... which causes enormous pain as you have described.
The problem with so many bad dentists today is that they don't have any chemistry background, and are clueless as to the toxic materials that they are putting into your mouth which cause the pain and also hurt your immune system.
The crown may also have heavy metals in it which are causing you pain and the glue used to cement the crown will also be toxic and cause pain.
You have three issues here:
1.) Badly done root canal that must be re-done properly.
2.) Bad crown materials and bad fit of crown
3.) Bad adhesive used to glue crown to your body.
A good crown is the "Lava" crown with "Noritake" added to it in the lab for perfect aesthetics. Another good crown is the "Diamond Crown."
ONLY a good Prostodontist should be putting crowns on.
Also, have a good dentist use Alginate to take your impressions. The impressions that many dentists use is made out of WOOD FILLER and is toxic.
Sounds unbelievable? It is totally outrageous.
A visit to the dentist can and will be hazardous to your health if you are not careful.
Mizzy Fleck is a good cement for crowns that most sensitive people can tolerate. Demand this. It can only be used with all porcelain crowns, which is what you want.
I have given you the brand names above.
Also, Diamond crown makes a good cement that should be tolerable and is certainly less toxic.
Good luck. Hope this helps.
more on my note to you. During a triple root canal proceudre tht went dismissed for nearly a year as pain from implants nearby, I was given novocaine injections that hit the nerve in the back of the jaw and caused heat and electric shock senation. That same evening, my cheek muscle and behind my eye started to spasm. The pain behind my eye, toward my ear and at base of skull on the same side were sharp, like a knife. That has continued through today. Spasms and pain are random, with no particular activity bringing on the 'eposides.' Endodontist told me to see a psychiatrist. Periodontist referred me to a neurosurgery specialist, whom I saw last week. He took notes, told me he didn't know if it would heal or not, and gave me a script for Neurontin, which I have not filled, and said some people have had good results with acupuncture. I had a dangerous episode today and was almost hit by a car. I called the endodontist, and they asked me to come in. It took ernest effort to get him to listen to me, and tested me when I told him that I also have almost no feeling on my cheek (hot/cold/sharp needle - no sensation). He then told me the nerve he injected and the one that controls areas of pain are 2 different nerves but right next to each other. He said perhaps there is inflammation on the nerves and gave me a script for a anti-inflammatory steroid to take for 6 days. He also said it could be TMJ (why now do I have it was my question - no answer), and that it could be a separate neuralgia from a cold or something). I understand your frustration and the feeling of despair when doctors dismiss real symptoms. Be earnest. It was hard for me to be because my boss is their patient, too, and he is the one who referred me (these are all top specialists in NYC). I'll post again after the dose of steroid. Best of luck, strength and good health to you.