Hi, At the age of 17 no one gets cancer of lung so be assured about this. But at the same time it is more important to find the cause for blood in nasal discharge, back ache and chest pain. The most common causes I can think about your symptoms is bacterial infection of nose and throat causing strep throat and the infection could have been spread to nearby structures. This given the symptoms of pain, myalgia, costochondritis and so on. Hence I would advise you the following in such a situation: Consult your Doctor, preferably an ENT Surgeon for clinical evaluation, examination and investigations if needed. To get started on an antibiotic, anti-inflammatory, symptomatic and supportive treatment on prescription. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. T. Chandrakant, General Surgeon