I have a feeling that akathisia is a teeny bit different for people. I've even had akathisia from different medications that I experienced a bit differently.
I suffered so much with akathisia from Geodon. It was odd, unlike the akathisia I had from Zyprexa and Abilify which started almost immediately, my akathisia from Geodon only started about 5.5 years after I started it. My psychiatrist kept me on Geodon for almost two more years. I, too, used Ativan because propranolol did nothing. Cogentin helped, but I had to stop it because of extreme constipation, that others I know never had from it.
I always woke up with akathisia. I'd take Ativan but had to wait 30-45 mins for relief. Those 30-45 mins were horrible!
I relate to this:
"[It comes] from so deep inside you, you cannot locate the source of the pain …" and this "You ache with restlessness, so you feel you have to walk, to pace. And then as soon as you start pacing, the opposite occurs to you; you must sit and rest. Back and forth, up and down you go … you cannot get relief …", but my pacing was more with Zyprexa and Abilify. With Geodon, I most often rocked back and forth in bed lying down. Maybe because I was too tired from Seroquel XR to pace. Akathisia was very tiring for me. Restlessness didn't really equal energy for me even though I had to move for a partial, but never full, relief.
I never experienced anything with my jaw or stiffening spinal cord. For me, the restlessness was more a mental torture in my head. I'll agree that it was a type of pain for me. Severe restlessness is agonizing. My constant movement seemed to be from my hips down.
My psychiatrist did eventually take me off Geodon. That was the hardest medication I ever had to get off. It was a long process with withdrawals. I had been on a large dose of 160 mg for years. Maybe when I reached 60 mg the akathisia started to ease.
My quality of life has improved a lot since getting rid of akathisia.