✔ 最佳答案
It is very good for you to seek medical advice.
For this mass in axilla, it can be skin conditions like (lipoma, sebacous cyst etc.), and can be a lymph node, and can be breast mass if you are a lady. To differentiate these, it is essential to perform physical exam, i.e. to feel to mass by doctor.
Here is the causes of a lymph node found in axilla(for your reference)
Breast cancer metastasis
Lung cancer metastasis
lymphoma
breast or axillary infection
etc,...
If the mass is a lymph node due to cancer, earlier detection lead to earlier treatment and so better outcome occurs, so u better not neglect it.
for 睇e生睇咩科, i think better to see family medicine doctor家庭医生 or surgery外科.