my left shoulder is a tad sore too. not sure from what. could be any number of things I've done to myself. including, but not limited to, falling off my bike a cpl times (to the left). guy I used to work with was a little older than me but we would often joke about aches & pains from minor sports injuries. our on-going comment to ea. other was: "give it 6 months". so good luck with that