Pedestrians have no protection from the cars that hit them. Even if your pain is not that significant, you still need to get checked out by a physician for invisible injuries such as internal bleeding, organ damage, neck injuries, and traumatic brain injuries. Also, the adrenaline rush from a vehicle striking you likely masked your pain for some time. Seeking medical treatment also means you have documented your injuries in your medical record, which serves as valuable evidence for insurance companies and the court, if necessary.