What Could A Mass On Upper Lung Indicate?

Hi, I am 54 yrs old and have cad/w2 stents that are 12 yrs old . I have a lot of chest pain and also hurting in my upper back. When I move around (walking , doing housework,etc) my ribs feel like they are squeezing together. I have high cholesterol, high blood pressure, and was recently diagnosed with diabetes. I am on meds for all problems. I also had a left heart cath done in Dec. and was told everything looked good. Also Drs discovered a mass on my upper right lung in Dec. I saw a pulmonary Dr , and he told me my symptoms were not from my lungs. What should be the next course of action to figure out what is going on?