Are rotors always needed with rear brake pad replacement?

Hello, no, you don't "have to". If the rear brake rotors are solid - not vented - there is likely some material on there that can be resurfaced. Also, sometimes you can replace pads only and "scuff up" the rotor surface to accept the new pads, as they don't see the stress the front brakes do. I'd get a second opinion locally. Clearly, I couldn't know your vehicle's condition -- so it's difficult to speculate. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops