Hidden pain in right armpit should be alert to diseases such as right axillary lymphadenitis, right breast cancer or lung metastases. 1. Right axillary lymphadenitis: when inflammatory reaction occurs in the right axillary lymph nodes, such as axillary lymphadenitis, it mainly manifests as enlargement of the right axillary lymph nodes and tenderness, etc. If the inflammatory reaction is not obvious, it may manifest as mild pain or tenderness in the right armpit. If the inflammatory reaction is not obvious, it may show mild pain or hidden pain in the armpit. Therefore, when the right armpit has hidden pain, we should be alert to lymphadenitis. 2. Right breast cancer or lung cancer metastasis: for right breast malignant tumor and right lung malignant tumor, due to the metastasis of tumor cells with lymph, hidden pain in the right armpit can appear, and the pain symptoms will be aggravated in the later stage as well as lymph node enlargement and so on. There are many reasons that can cause right armpit pain, such as trauma, lymphoma, bone cancer, cervical spondylosis, etc., which can lead to right armpit pain. Therefore, you should go to the hospital for medical consultation to clarify the cause of the pain, and then follow the doctor’s instructions for treatment.