What is the likelihood of having lung cancer with a clear chest xray and normal blood work? only real symptom is sob but clear echo 15 months ago

Depends on risk: Chest xrays are not good tests to rule out lung cancer and neither is blood work. But at 32 your risk of lung cancer is very low. Even a heavy smoking history would not increase your risk to the point that it was likely that you had it as a cause of shortness of breath.

Low risk so far: Based on what you explained so far, your risk seems pretty low. This is especially true if you are a non-smoker, and if you have a low family history risk, and if you have no other history of toxic environmental exposures. However, your shortness of breath may still need to be worked up over time, and even I can't accurately predict your cancer risk with 100% certainty. Continue your routine care

Not likely at 32: At 32, it's very unlikely that you have lung cancer. Especially if you have no weight loss, no sweats and are not coughing up any blood. If you smoke, you can further reduce your risk by quitting! There are many causes for shortness of breath, so talk to your doctor about any further evaluation you might need.