What are the symptoms of lung cancer in a non-smoker?

When my husband was diagnosed with Stage 4 Adeno Carcinoma, lung cancer there were two things that were prevalent. One is an annoying cough and the other, unexpected one, was terrible pain in his legs. We found that when oxygen is lacking, the body shuts down the extremities. They only found the cancer after they did a clip of his lung and did a biopsy. He lived another agonizing nine months.