I had severe pain in both shoulder blades prior to diagnosis (lc was found in my right lung, pain was first in my left shoulder, then also in right). It was the worst pain I have ever felt when I moved certain ways (like trying to turn over in bed at night).
MY diagnosis came because of a car crash and the CT scan they did in the ER. After starting chemo, the pain went away. Now that I am off chemo (tumors are about half the size, but still there), pain is back slightly, but not like it was.
I have since read that back and/or shoulder pain CAN be the first sign of lung cancer.