Rotator cuff injuries cause pain in your shoulder and upper arm. The pain may be most noticeable when you reach up or out. When you turn your arm as you lift it, the tendons are more likely to rub against surrounding structures.
The essential difference between the original series of AF Nikkor lenses and all AF lens types introduced subsequently, from the AF-D versions onwards (see below), concerns the compatibility of a particular lens with Nikon's enhanced Matrix metering system known as 3D Matrix metering that was introduced during 1996.
So to be fair to Nikon it isn't really their products anno 2016 that are holding them back, but the fact that Canon achieved a greater market share in the early years and a large collection of lenses will make most professionals stick with the same brand - even if Nikon were to offer a significantly better camera at some point it would be rather expensive to switch over.