The body is very intricate and there are many reasons why someone might be feeling radiating pain or weakness in the upper body. I like this article showing some simple tests to do. As always stay in the scopes of your training. This is a nice read.
Identify Upper Extremity Nerve Entrapment Syndromes
From time to time I find articles that I like and I love to share them and from time to time I like to blog myself... enjoy!