this is why I said you confuse two

1.  "duty to retreat" is the opposite of stand your ground law.  That is, in public places, you have a duty to retreat or you can stand your ground during a confrontation. 

https://en.wikipedia.org/wiki/Duty_to_retreat

"This requirement contrasts with the right in some other jurisdictions to stand one's ground, meaning being allowed to defend one's self instead of retreating."

2.  Castle doctrine means "your home is your castle", that you can defend your home (note, not your real estate property, but the home where you live) with deadly forces.  This is true for most states, of course details might vary. 

"In all duty to retreat states, the duty to retreat does not apply when the defender is in their own home. In Connecticut, Delaware, Hawaii, Nebraska, and North Dakota, the duty to retreat does not apply when the defender is in their workplace. States may have both a Castle Doctrine and a Stand Your Ground variation, such as Iowa."

https://worldpopulationreview.com/state-rankings/castle-doctrine-states?

3.  So where is the confusion?

The confusion lies in advocating "stand your ground" law.  Advocate want to pass "stand your ground" law as an extension of "castle doctrine". They say you should be defend your body just as you defend your home.  It is complete BS.  Home carries special meaning in all cultures, while allowing a fight in public space under stand your ground law when guns are everywhere is just dangerous.