I'm just started my clinicals and while I am able to hear heart and bowel sounds, I am having difficulties differentiating between normal and adventitious lung sounds, especially over women who are obese or big breasted. At first I thought it was my stethoscope but I had the same problems with other stethoscopes. What is it that I am possibly doing wrong or what can I do to improve on this topic? I've tried listening to the lungs on the simulation dolls at school and youtubed videos but it's so different when you hear it over a patient.