There are two cases of arm pain from lung cancer, which are commonly analyzed as follows: one is lung cancer in the apical part of the lung, which tends to directly invade or compress the shoulder tissue, resulting in arm pain; the other case is lung cancer occurring in the shoulder bone metastasis. These pains are hidden pains, a kind of pressure and confinement hidden pains, which are different from experiencing sharp pains from sharp injuries and needle stab wounds in daily life. Moreover, if there is no drug intervention, they are usually persistent and continue to come on day and night vaguely, which have been constantly troubling the patients.