"Where" does back EMF appear in motor?
The back EMF is generated in the wire that makes up the coils of the motor.  When a wire is swept sideways thru a magnetic field, a voltage is generated along the length of the wire.  Spin the motor with just a voltmeter connected, and you will see it make a voltage.

So yes, the resistance and the back EMF are actually distributed along the wire in the coil.  There are lots (infinity, actually) of little resistances in series that each get a little voltage in series with them when the motor turns.

Viewed electrically from the outside, this can't be distinguished from a lumped resistance in series with a lumped voltage source.  Since this is simpler to draw, think about, and analyze, that's how motors are usually shown.