Upper back pain severe at times with spasms. Occ. Chest and stomach pain too. Ekg. Chest xray. Heart enzymes. Labs. Negative. Still worried. Lung cancet?

Unlikely. The chest x-ray would show something in the case of cancer. In middle age back pain is usually related to the spine and muscles. Discuss your concerns with your physician.
Could be your. Kidney, pancreas, lungs, spinal nerves, etc... Explore further...Also the tests you went thought are not enough to rule out your potential heart problems. The best option is multifunction cardiogram. http://en.m.wikipedia.org/wiki/multifunction_cardiogram wishing you the best luck!