I recently noticed that when I apply pressure to the rear brake lever that it seems to be a little stiff, maybe even a little resistant and when pushed it will sometimes not spring back, but rather come back very slowly. Can anyone tell me what I should look at to investigate this?

 

Sounds like it might be time to rebuild the master cylinder, but I would start with thoroughly cleaning the linkage and caliper.

 

My friends 07 Street Bob with 61,000+ miles was doing the same thing. He removed the master cyclinder & cleaned out the resevoir, dis-assembled the forward control brake pedal & cleaned the rotating parts.
Re-installed evey thing with freash brake fluid.
Problem solved.

 

Looks like I am going to be taking it in, the bike is still under warranty!!! The bike is a 2010 with 18k miles on it.