A lump on the back of shoulder without pain or itching is considered to be related to lipoma, soft fibroid and dermatofibroma. 1. Lipoma: patients will appear multiple or single lumps, preferably in the shoulder, back, etc. The cause of the disease is not yet clear, and may be related to tumor-causing factors active, heredity, systemic lipid metabolism abnormalities and other factors. 2. Molluscum contagiosum: the cause of this disease is not clear, may be genetic, obesity, and viral infection, diabetes and other factors, the patient’s skin will appear above the skin surface of the proliferation of organisms, in the form of balls, pockets, etc., preferably in the neck, trunk and other places. 3. Dermatofibroma: the etiology of this disease is not yet clear, mostly considered and insect bites, viral infections and trauma and other factors. The patient’s skin will appear firm nodules, ovoid, round, generally no conscious symptoms, some patients will appear in the neck and shoulder. There is no one reason for a painless and itchy bag on the back of the shoulder, and patients are advised to go to a regular hospital to clarify the cause of the disease.