I too have arm weakness. When my problems reared their ugly heads, I did not have the ability to work my right hand and fingers. Not sure how it affected my whole arm, because it was more obvious w/the hands at that time. I had the clumbsiness along with other issues to the degree that I couldn't write with a pen or pencil. This problem was not obvious to me until I was in the middle of writing, or going to pick something up. I would get a sensation, and then not be able to finish make them work until the sensation passed. Was very frustration, because all would come to a halt. Those sensations would last for seconds or minutes at a time all day with no ryhme or reason.
Now, and it's been months since then, that problem has rectified for the most part, however, I have left side pain in my arm that comes from the top of my shoulder and radiates down. I think it's related to my neck.
I don't have many coping mechanisms to rely on, as it's hard to know where to put the durn things and find relief. I adjust positions, move them around, try to keep the blood flowing etc. I also find that w/the arms, sitting contributes to my pain, stiffness, and lack of mobility. So, I get up and down a lot throughout the day, do some shoulder/arm rolls, but really it's just temporary relief. Sometimes, nothing helps and it's just a dull ache that won't go away, and the hands just feel stiff and heavy. I figure I'll take that symptom over not being able to get my brain to get them to work any day. . . I hope that never returns.
I take naproxen too, but it doesn't help much. Wish I had more to offer, so it's good you bring up the issue. Maybe more will tell us what they do to help.
Yes, I know that scary feeling of not being able to get your hands to work. That has bothered me more than anything else. Thanks for the input!