Background: Breastfeeding has various benefits for infants and mothers. However, if not performed in the correct posture, prolonged breastfeeding could cause musculoskeletal-related symptoms such as shoulder, neck, and upper back pain. In Jordan, nursing mothers do not have access to a breastfeeding midwifery team, a breastfeeding dietician, or a breastfeeding nurse for advice and education. The primary aim of this study was to explore nursing mothers' experiences of breastfeeding-related musculoskeletal pain; secondary aims were to explore nursing mothers' awareness of recommended breastfeeding postures and their experience of education and advice about breastfeeding postures. Methods: A cross-sectional mixed methods study was conducted with nursing mothers in Jordan who have breastfed their babies for 6 months or more following normal delivery, using an online survey questionnaire and semi-structured interviews. Participants were recruited through general practitioner clinics. Results: Four hundred ninety-three nursing mothers submitted the online questionnaire, and 12 interviews were completed. Nursing mothers reported experiencing nonspecific pain in lower back, neck, shoulder, and hand, attributed to breastfeeding. Pain in these joints affected mood, sleep, working ability, and quality of life by limiting activities of daily living. Findings showed that the majority of Jordanian nursing mothers did not receive education about safe or optimal breastfeeding positioning from health professionals. Conclusions: Nursing mothers in Jordan are not receiving appropriate education or advice about optimal postures for breastfeeding and have reported experiencing musculoskeletal pain, attributed to breastfeeding, that interferes with activities of daily living and affects quality of life. Postural education and advice should be provided to nursing mothers to prevent or avoid development of musculoskeletal pain.