Relieve pain, prevent injury, and increase performance. Get customized mobility coaching developed by Dr. Kelly Starrett.
These issues will have a lot to do with the environmental load of your job as well. You may have some issues in the neck and the nervous system that are the root of the problems as you describe pain and weakness that sounds like a nerve tension/irritation related problem. Look into the website on the things you can do for people in water sports, there is a category specific to that on the new website, thereadystate.com.