Weakness Throughout Arm During Activity

[Zinator]

My problem began when I struck my right hand against a lane line while swimming 4 years ago.  Ever since that event, my arm gets a weak sensation throughout itself, which only worsens as I continually move my arm while swimming. Constant movement like arm circles, or keeping my arm in a raised position creates a sensation of weakness, which worsens the longer I do the activity. I have noticed that when doing arm circles with both arms, my right and left scapulae are synchronized as my arms move together, but as I continue, my scapulae become desynchronized despite my arms being in sync. I have also noticed a burning sensation in the right wrist while swimming, and a cramped feeling in the muscle between the thumb and pointer finger. My right shoulder seems to be lower than my left when looking in the mirror, which I believe was not the case before the injury. This seems like a nerve issue, but I am not sure. When writing, or not having my arm supported by the table, the weakness sensation emerges. I have not noticed a strength issue with my right arm, but through continuous movement the burning and weakness sensations in my wrist, shoulder, neck, and throughout my arm become unbearable. When raising my arms straight above me, the right arm gets the sensation very quickly, and the muscles around my shoulder feel very week. This weakness runs through my entire arm, but also, I feel it in the right side of my neck as well.  I want to be able to swim again without the burning and weakness sensations emerging.