Thank you for your question. I look forward to working with you to provide you the information you are seeking for educational purposes only.
I am a DIFFERENT CONTRIBUTOR. Your previous expert was correct in that there is no black and white issue here. The OK courts look at whether or not "but for" the actions of the other driver your car would not have been damaged. Thus, the car that hit you can indeed be liable to you, but you have to prove that they did not leave reasonable distance between your car and their car and had they done so then they would not have hit your car when the other car hit them.
There is no way to provide a "yes" or "no" answer on negligence liability in the case you describe. You have to prove that the car behind you that hit you did not have sufficient space and based on the speed of the third driver as well that they should have been far enough behind you to avoid contact with your vehicle when struck by the third vehicle.
Your insurance company would love to have it so in all cases the vehicle that started the chain reaction was liable for all damages, but that is not necessarily the law. In OK the courts look at each collision as a separate accident for which ultimately through various actions the driver that started the chain collision may be responsible, but how it works is this:
Vehicle 1- 3rd vehicle that started accident
Vehicle 2- middle vehicle
Vehicle 3- your vehicle.
Vehicle 2 is liable to Vehicle 3 for damages, but Vehicle 1 is liable to Vehicle 2 for damages, which includes reimbursement of whatever Vehicle 2 had to pay to Vehicle 3 for their damages. If Vehicle 1 flees and cannot be found, then Vehicle 2 is still liable in most cases for damages to Vehicle 3.