This is usually the first sign of thoracic outlet syndrome.(TOS) Extended rest will resolve this most of the time.
Brachial nerves will get pinch through inflammation. This originates in the neck and color bone area. Classic sign is tingling, nerve shock, numbness in middle , pointer finger and thumb.
Always remember pinky finger and ring finger are usually elbow issue.
Middle, pointer finger and thumb is usually neck and coller bone area. For nerve issues. Hope this helps others.