You were rear ended and pushed into the car in front of you who is at fault?

Well it would of been the person behind you. Because they was not looking at your car which means it is there fault. Different jurisdictions handle this differently, but the overall outcome is the same.

1) In some jurisdictions the middle car is held At Fault as they still struck the car in front of them, however they allow the middle car to pay the first car and then claim that along with the middle car's damages against the back car.

2) In other jurisdictions they allow the middle car to claim an "Interpleader" that transfers the responsibility to the back car.

I know this sounds complicated but it is simply how the court and insurance companies assign responsibility through the chain of events.