Hello, Thank you for trusting HealthcareMagic for your health concern Such significant weight loss along with chest/lung pain raises the concern for underlying lung malignancy, especially if you are or had been a smoker. Other causes of rapid weight loss including hyperthyroidism, chronic infection like tuberculosis, inflammatory disorders, diabetes should also be considered. You will need complete physical examination, chest Xray, complete blood count, ESR, complete metabolic profile and thyroid function test done at this point . Please be advised to follow up with your primary care provider for further evaluation and management. Hope this answers your questions Please address further questions here Regards Dr.Lekshmi