I am Dr Zaheer (Doctor of homeopathic medical science) and I can help you by describing best homeopathic medicines / remedies
Kindly read my first part of my answer below……..
I have studied your question / all provided information and found you can try 100% side effects free and natural homeopathic remedies (Chamomilla 200C, Cuprum Metallicum 30C) to treat and cure YOUR PRESENT CONDITION as you mentioned (severe muscle spasms, coming from the neck, attaching to those muscles on top, around and under the clavicle. I can no longer lift my left arm above horizontal.)
If you use remedies as I am going to describe and follow dose and instructions strictly then you will get best results
Remedy Chamomilla 200C is our best remedy when there is no pain relief even after use of strong pain killers; this is the remedy which can relieve severe pains
Remedy Cuprum Metallicum 30C is the remedy when there is severe muscular spasms so these are Best of the best remedies for you, according to your needs, and you can try them with full confidence.
So arrange homeopathic remedies (Chamomilla 200C, Cuprum Metallicum 30C)
(How to arrange remedies)
You can arrange remedies from any near homeopathic pharmacy and you can also order remedy online.
If you agree to try my described homeopathic medicines / remedies then reply me, and I will write you 2nd part of my answer dose schedules, and all needed instructions.
Waiting for your reply,