Hard lumps that move under the skin may be caused by lipoma, lymphadenitis and epidermal cysts. 1. Lipoma: it can be seen in any part of fatty tissue, mostly manifested as localized lumps, which can be slightly moved by pushing fingers. Its cause is not yet clear, and it may be caused by activation of tumor-causing factors, heredity and other factors. 2. Lymphadenitis: mainly manifested as pain, enlarged lymph nodes and other symptoms, and some patients may feel hard lumps moving when touching under the skin. Its etiology may be related to infection. 3. Epidermoid cysts: typical symptoms are dome-shaped elevated skin swellings, some of which may be subcutaneous, moderately hard, movable, and may develop in various parts of the body. Epidermal cysts may be formed due to factors such as skin damage. There are more reasons why there are hard bumps under the skin that move, and patients are advised to seek medical examination to clarify the cause of the disease.