Physical examination for more data is recommended. Whether the skin above the lump is red, hot or painful is very important. Also, it is important to check if the lump moves together with the rest of the skin.
Breast cancer is a cancer that starts in the breasts. It might origin from the glandular tissue that produces milk or from the connective tissue. In both cases, a lump is usually found in the breast. Often the lump is detected by touching for the first time. Other symptoms that might be present when having breast cancer include: skin changes above the lump (if the lump is located close to the skin), discharge from the nipple, and asymmetry of the breasts due to enlargement of the affected breast and lump or lumps in the armpit. The lumps in the armpit might be metastasis originating from the breast cancer. They mean that the breast cancer have already grown enough to spread out of the breast. Metastasis in other locations might be found at the same time if the person is examined adequately.
However, not every enlarged lymph node in the armpit is breast cancer metastasis. If there is a inflammation in the vicinity, then the adequate lymph node might react by enlarging, swelling and inflaming themselves. A small skin wound close to the armpit might cause this condition.
Enlarged lymph nodes are often seen in some rather less serious conditions like ingrown hair. If you shave your armpit, then there might be ingrown hair that has caused skin inflammation and reaction from the lymph node.
Physical examination for some local skin problems is necessary from a family doctor. As for the breast cancer, you might be referred to specialist for breast cancer or thoracic surgeon for physical examination and other diagnostic procedures (mammography, breast ultrasound, and ultrasound guided biopsy). The results might determine whether you have breast cancer at all, and if you have what stage it is. The stage is important for determining the treatment.