A sudden bulging of a hard bag above the chest may be lymph node swelling, neurofibroma, costochondritis, etc. It is recommended to consult a doctor in time for treatment. 1. Enlarged lymph nodes: a sudden bulge of a hard bag above the chest may be caused by inflammation and infection of the lymph nodes, swelling, forming a hard lump, which will have obvious pain when touching. 2. Neurofibroma: when suffering from neurofibroma, sometimes it will lead to a bulging hard bag above the chest, and it will be painful when pressed, and with the development of the disease, it will grow more and more. 3. Breast malignant tumor: If an elderly female patient has a hard bag above her chest, it may be a malignant tumor of the breast, and the hard bag is not easy to push. Sudden bulging of a hard bag above the chest may also be other reasons, it is recommended that timely medical examination, under the guidance of the doctor to choose the appropriate treatment program, so as to avoid aggravation of the condition.