I always start my winter lifting schedule with a couple of weeks of light lifting - lots of reps (12-15), not a lot of weight to build a base. If I start lifting heavily without a base, I'll be stiff & sore. I'm wondering if that might be your case also? Tendons & ligaments adjust more slowly than muscles. I see lots of sore rotator cuffs in the gym - you can tell those because the guys are "doing the chicken" - holding their shoulder and rotating their elbow - between lifts.

When I started to get as serious with my winter training as I am with my cycling, I saw great results. It's too bad, though, that we're wearing all these sweaters that cover up our great delts & biceps!