The person who ran into you from behind of course because they should be stopping, or slowing down when you turn in the parking lot.
It is your fault.
Need more details about the incident, such as whether or not you drifted into another lane, and whether you were bumped by someone changing lanes, someone turning behind you, someone already in the lane you were turning into, etc.
Usually their is no fault associated with parking lots. I'm sure your insurance company looks at it as your fault.
The person backing out. If you were in the lane/road behind them they needed to use caution when backing out.
You are.
Depends on the jurisdiction, but typically, two vehicles backing up is a 50/50.
Backing up--it is your fault.
is fault of car behind the second car not yours
The car that is in motion is ALWAYS at fault.
You if you were backing up. If you were waiting at a stop sign or stoplight or even an entrance and someone else hit you, it would be the person behind's fault.
Answering "Pulling out of a parking lot onto a street and you have to back up to avoid on coming car and the car behind you hits you who is at fault?"
The guy from the parking spot because he is looking behind him for oncoming traffic. The guy coming out of the alley wasn't too bright either. Think about it.