I recently went to the ER for high fever, but they said I was in the late stages and there wasn t much they could do. They gave me some tylenol and my fever went down. It s been a few days since then and I have a severe sharp pain around my left collar bone and my left side when breathing, burping, swallowing, and various different movements, as well as pain sometimes in my left leg. I don t know if this is related to having influenza, but it s making me kind of nervous. Do you know what the cause of this might be?