When I was in a car accident a few years back, I got out of the car by myself, and didn't feel any pain til after my adrenaline rush subsided. Once I calmed down, I started noticing bruises, scrapes, that kind of thing, as well as the fact that my back sort of hurt, but in a tight muscle sort of way. The moment the ambulance got there, they asked "does your back hurt?" I said a little, but only achy. they collared and strapped me to a backboard anyway, despite the fact that I'd been walking around, and as a result all my injured muscles got stiff, causing me more pain. It sucked, and I felt like it was pretty unnecessary.