Participants in this group will receive Connective Tissue Massage. The intervention will be applied to the sacrolumbar, lower thoracic, abdominal, and anterior pelvic regions. Sessions will be performed five days per week during the Cycle 0 premenstrual intervention window, from the estimated ovulation day, calculated as cycle length minus 14 days, until Cycle 1 Day 1. Each session will last approximately 10-15 minutes.

Participants in this group will receive music-based Progressive Muscle Relaxation Training. Participants will receive face-to-face instruction at the beginning of the study, and the first session will be conducted in person. Thereafter, participants will perform the training using approved audio recordings from the Turkish Psychological Association. Sessions will be performed five days per week during the Cycle 0 premenstrual intervention window, from the estimated ovulation day, calculated as cycle length minus 14 days, until Cycle 1 Day 1. Each session will last approximately 20-30 minutes.

Participants in the control group will not receive any intervention during the study period. They will be asked not to receive complementary interventions that may reduce menstrual pain or promote relaxation, such as acupuncture, massage, or other mind-body techniques. Participants will continue their routine daily activities without restriction. After completion of the study, participants in the control group will be offered Connective Tissue Massage or music-based Progressive Muscle Relaxation Training according to their preference.

Connective tissue manipulation will be applied to the sacrolumbar, lower thoracic, abdominal, and anterior pelvic regions. The intervention will be performed five days per week during the Cycle 0 premenstrual intervention window, from the estimated ovulation day, calculated as cycle length minus 14 days, until Cycle 1 Day 1. Each session will last approximately 10-15 minutes.

Participants' menstrual pain intensity will be assessed using the Visual Analog Scale (VAS). Participants will be asked to rate the average pain intensity experienced during the first two days of menstruation, the average pain intensity experienced throughout the menstrual period, and the worst pain intensity experienced during menstruation. The VAS is widely used in clinical practice and scientific research to assess pain perception. Scores range from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Higher scores indicate greater pain intensity and therefore a worse outcome.

The Pain Catastrophizing Scale will be used to assess catastrophizing related to menstrual pain. The scale consists of 13 items and three subscales: helplessness, magnification, and rumination. Participants will be asked to rate the extent to which they experienced each thought or feeling during menstrual pain on a five-point scale ranging from 0 to 4. Higher scores indicate greater pain catastrophizing.

Participants' satisfaction with the Connective Tissue Massage or Music-Based Progressive Muscle Relaxation Training interventions will be assessed using a 10-cm Visual Analog Scale through two questions: "How satisfied were you with the overall treatment you received?" and "Would you recommend this treatment and/or advice to someone you know who suffers from menstrual pain?" Scores range from 0 to 10, with higher scores indicating greater satisfaction or stronger recommendation.