Hello and thank you for your question. Have they performed an MRI of the neck? Do you have any medical problems? Any trama prior to this onset of symptoms?
I would want to know the results of the MRI of the neck especially since you have stiffness there. It's important to look for possible herniated disc(s) with pressure on the nerves or spinal cord.
Sorry to hear that. I don't think the symptoms should be related to the IVF.
I think the neurologist visit is a good idea. Make sure to bring all your imaging studies with reports when you go. Again, I would want to make sure your symptoms are not originating in your neck. A neurologist may also perform nerve conduction/EMG studies of the arm(s) and leg(s) to see if there is any nerve irritation. Otherwise, not much to do until it's more clear what is causing it.
Happy to hear you are not in pain. I would recommend a similar workup even with left arm involvement.