My new bike is about 4 months old and after longer rides I am getting sore shoulders. But it's not a joint/bone issue- it's my shoulder muscles. There is no 'pain'- just working the muscles more than on my old bike.
I can see that my shoulder muscles on either side of my neck are getting bigger each month. For me, the shoulder soreness is just the same as when I do a lot of climbing on rides and my leg muscles are sore the next day or two....so it's actually a good thing!