Pain along medial aspect of arm in a post - mastectomy patient is due to:

Four Pain Syndromes have been Distinguished: Phantom Breast Pain: Painful (often knife like or shooting) sensation that the removed breast is still present Intercostobrachial neuralgia: Usually known as post-mastectomy pain syndrome (PMP), consists of pain in axilla, medial upper arm and anterior chest wall and is often is caused by nerve damage during axillary node dissection. Neuroma Pain: Can occur from scars from either mastectomy or lumpectomy but is more common if surgery is followed by radiotherapy. Other Nerve Injury Pain: Can occur even if intercostobrachial nerve is spared and is more common in breast reconstruction and implants.