well when muscles are over stressed they grow and strengthen so if you are in pain then I'd say it's not the muscles. How long did you have to use extra arm power? how long since you stopped having to use extra arm power? It's like in the gym if you do a new exercise you will be stiff the next day for a few days, then next time you do it it will be easier and less painful afterwards after that you can use more weight and so on, that's how muscles grow. So I'm curious as to why you would still be feeling it.