Following a car accident, soreness generally lasts around six weeks or longer. It is imperative that patients follow the advice of the doctor treating their injuries. Testing for injuries after an auto accident may include: - Range of motion tests - X-rays - Magnetic Resonance Imaging (MRI) Failing to follow your doctor’s instructions does not only prolong the length of time of soreness and pain but can also give the insurer reason to deny an insurance claim. A doctor can track the progress of your healing and send you for further examinations, should your injuries not heal within a reasonable time frame.