Shoulder Pain
Many individuals believe that shoulder pain is caused by a physical injury. Shoulder pain, on the other hand, might be a warning sign of lung cancer that should not be overlooked. A lung tumor that has migrated to the bones in and around the shoulder or spine can also cause shoulder pain. If you have a huge tumor in your lung, it can press on adjacent structures, causing shoulder pain.
Some shoulder pain occurs when the tumor puts pressure on the spinal nerves in the lungs. The brain then processes the pain signal and assumes the cause is from the shoulder, even though the pinched nerve is in the lungs. This condition is referred to as referred pain, i.e. the localization of pain does not coincide with the localization of the stimulus in the sensory system.
Lung cancer can cause severe shoulder pain, especially if you smoke, the pain will manifest itself as: Present even at rest, not related to any strenuous activity involved to the shoulder occurs at night, no signs of improvement after a few weeks.