Background <p>Pain is a common and clinically relevant symptom during chemotherapy for breast cancer, negatively affecting quality of life. Although physical exercise is recommended and considered safe during chemotherapy, it may acutely exacerbate pain while potentially reducing it in the long term. Therefore, this study aims to systematically review the acute and chronic effects of physical exercise on pain outcomes in breast cancer survivors undergoing chemotherapy.</p> Methods <p>This protocol follows PRISMA-P guidelines. Searches will be conducted in PubMed, Excerpta Medica dataBASE (Embase), Scopus, Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL). Eligible studies will include randomized controlled trials enrolling adults with breast cancer undergoing chemotherapy who participate in structured exercise interventions and have pain assessed using objective and/or subjective measures. Risk of bias will be assessed using Cochrane risk-of-bias tool for randomized trials, version 2 (RoB 2), and certainty of evidence using&#xa0;Grading of Recommendations Assessment, Development, and Evaluation (GRADE).</p> Discussion <p>By distinguishing short- and long-term effects, the review aims to clarify the role of exercise in pain management during treatment. Anticipated heterogeneity will be addressed through structured risk of bias assessment, subgroup and sensitivity analyses, and evaluation of evidence certainty.</p> Systematic review registration <p>The protocol is registered in PROSPERO (CRD420251102981).</p>