question: I am 46 and have been experiencing a dull pain in my left lung off and on for the past 3 weeks..Monday Morning I went to the er..and they checked for a blood clot--which was negative..they did a lung x-ray but did not give me the answer to that they did blood work and then perscribed Diaxon....is this for a lung infection?..before I could ask the doctor he was gone..