Hi, I have an 18 year old son. This past weekend, he came down with flu like symptoms. Fever (103), sore throat, and a pain in his chest left side, under the pectoral muscle. Hurts hurts when he breathes, radiates through his back, hurts to stretch. The flu like symptoms since Saturday, chest pain started Sunday with residual light pain on Monday, then none. Slept most of the weekend and today but around noon the pain returned and is quite severe.