Sometimes the effects of a whiplash injury are not fully realized immediately. There are several reasons for this. First off, the muscle and ligament stretching and tearing above causes the human body to go into a healing mode. Your body begins to produce fluids in the damaged area. Swelling occurs and the site of injury. As your body stiffens up from these effects, you often begin to feel more and more discomfort. This may take hours or even days. Second, you may be in shock after an accident and/or have substantial adrenaline that makes you less in tune with your body's immediate condition.