Short stray hairs

They could just be new hairs growing in.  My halo got much worse after I became a compulsive duster and was dusting off damaged hair too close to my scalp.  But if you don't do that, you will still always have some.  If you really have a lot that are all the same length, it could be that you damage it in some way (usually this would be with an accessory, not brushing. 

If you do hear hairs pop when you brush it, it might help if you start lower down and work your way up more gradually.