The causes of hard lumps in the flesh of the arm that are painful to press include abscesses, cysts, lymphadenitis, lipomas, etc. The treatments include medication and surgery. 1. Abscess: If the abscess is triggered by bacterial infection, metronidazole, ornidazole and other drugs can be given antibacterial treatment. If necessary, incision and drainage. 2. Cysts: if the cystic hyperplasia is caused by various factors, the cysts will compress the surrounding tissues, so there is pain and other discomforts after pressing, and it is necessary to give surgical resection of the cysts. 3. Lymphadenitis: Inflammatory reaction caused by inflammation in other parts of the body spreading to the lymph nodes in the arm, there will also be hard lumps in the arm flesh and pain when pressed. At this time, you need to actively search for the primary lesion and timely treatment. 4. Lipoma: a kind of benign subcutaneous tumor formed by the accumulation of mature fat cells under the skin of the arm, with medium-hard texture, which may also appear as hard lumps in the arm and painful when pressed. At this time, surgical excision is required. Finally, if you have hard lumps in the flesh of your arm, please consult a doctor in time, and please follow the doctor’s instructions to use the above medicines.