Exercises to help with hands and shoulders?

My last job was at a lumber mill where I was the lead grader on a Paul saw, I had to flip every board and grade it. After two years I had strained a shoulder muscle and had reduced finger dexterity, eventually I left and after a while got here. Saturday I did my route and then a piece of another route that included plums and two coverages, after doing all of the plums for my route. Now my fingers and especially my thumb muscles and the same muscle I strained before are giving me a lot of trouble. What do you guys do to help with these things?