Mild regurgitation will not cause chest pains. Moderate to severe regurgitation may cause chest pains, shortness of breath, etc. So a failing aortic valve may cause a variety of symptoms including shortness of breath, chest pain (angina pectoris), and dizziness or loss of consciousness (passing out).
An advanced condition can develop valve stenosis (narrowiing) and a narrow valve makes the heart work harder just to pump the blood through the valve to the body. A leaky valve lets blood back into the heart after it has been pumped out. The heart must therefore pump more blood forward to make up for the blood that is leaking backwards. With either condition the left ventricle will enlarge, and if untreated the enlarged heart will lose its contractility and reduced cardiac output leading to heart failure if not treated.
Your daughter's doctor would be in a better position to determine the underlying cause.