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.
Understanding old Nikon lenses: AI, AI-S, AF and AF-S. If you have any interest at all in using older Nikon lenses, you probably have some understanding of the difference between non-AI, AI, AI-S, AF and AF-S lenses. The trouble is that places on the web that explain the differences easily get lost in the details.