Dear Summer,
Without evaluating you, I cannot tell you what the cause of your chest pain is. I also cannot say if the leg pain is related, or not. I can say that most pediatric and adolescent chest pain that is sharp and worse with inspiration is typically noncardiac chest wall pain. We don't know what causes it, but it's mostly a nuisance and not associated with any disease process. You are 18 now, so you are at age of majority. This means that you can find your own doctor locally and have an evaluation for this. If you feel that a primary care provider is not able to give you adequate answers, then you can find a cardiologist to evaluate you further.