Inclusion Criteria:  Age ≥18 years old Undergoing a unilateral or bilateral lumpectomy or mastectomy, inclusive of all pathologies, including prophylactic surgery (e.g., family history or BRCA gene mutation)  Exclusion Criteria:  Previous breast surgery within 6 months of index surgery Undergoing any autologous flap procedure during index surgery Presence known chronic pain disorder involving surgical site or ipsilateral chest wall, shoulder, or arm during the 3-months prior to index surgery Documented hypersensitivity or allergy to lidocaine Surgery not planned to be performed under general anesthesia and/or planned use of regional or neuraxial anesthetic techniques before surgery (i.e., epidural, paravertebral, serratus plane block, pectoralis or modified pectoralis block) History of ventricular tachycardia, ventricular fibrillation, or atrioventricular block without a pacemaker Known cirrhotic liver disease Pregnant Unlikely to comply with follow-up (e.g. no fixed address, language difficulties that would impede valid completion of questionnaires, plans to move out of town)