Martin is a 58-year-old smoker who was admitted to the hospital with worsening shortness of breath over the last 2 days. he states that he is having some chest discomfort. the nurse asks him further about this in order to characterize whether this may be cardiac related, musculoskeletal related, or respiratory related. martin states that when he breathes in, he feels as if the air passing into his lungs is burning him. it is also very painful to swallow. based on what martin is stating, which illness does the nurse suspect is causing martin's chest discomfort?