Background and Objectives: Chronic pelvic pain (CPP) represents a major public health problem for women with a significant impact on their quality of life. In many cases of CPP, due to gynecological causes-such as endometriosis and vulvodynia-improper pelvic floor muscle relaxation can be identified. Treatment of CPP with pelvic floor hypertonicity (PFH) usually involves a multimodal approach. Traditional magnetic stimulation has been proposed as medical technology to manage muscle hypertonicity and pelvic pain conditions through nerve stimulation, neuromodulation, and muscle relaxation. New Flat Magnetic Stimulation (FMS)-which involves homogeneous rather than curved electromagnetic fields-has the potential to induce sacral S2-S4 roots neuromodulation, muscle decontraction, and blood circulation improvement. However, the benefits of this new technology on chronic pelvic pain symptoms and biometrical muscular parameters are poorly known. In this study, we want to evaluate the modification of the sonographic aspect of the levator ani muscle before and after treatment with Flat Magnetic Stimulation in women with chronic pelvic pain and levator ani hypertonicity, along with symptoms evolution. Materials and Methods: A prospective observational study was carried out in a tertiary-level Urogynaecology department and included women with CPP and PFH. Approval from the local Ethics Committee was obtained before the start of the study (protocol code: MAGCHAIR). At the baseline, the intensity of pelvic pain was measured using a 10 cm visual analog scale (VAS), and patients were asked to evaluate their pelvic floor symptoms severity by answering the question, "How much do your pelvic floor symptoms bother you?" on a 5-answer Likert scale. Transperineal ultrasound (TPU) was performed to assess anorectal angle (ARA) and levator ani muscle minimal plane distance (LAMD). Treatment involved Flat Magnetic Stimulation alone or with concomitant local or systemic pharmacological therapy, depending on the patient's preferences. FMS was delivered with the DR ARNOLD system (DEKA M.E.L.A. Calenzano, Italy). After the treatment, patients were asked again to score the intensity of pelvic pain using the 10 cm visual analog scale (VAS) and to evaluate the severity of their pelvic floor symptoms on the 5-answer Likert scale. Patients underwent TPU to assess anorectal angle (ARA) and levator ani muscle minimal plane distance (LAMD). Results: In total, 11 patients completed baseline evaluation, treatment, and postoperative evaluation in the period of interest. All patients underwent eight sessions of Flat Magnetic Stimulation according to the protocol. Adjuvant pharmacological treatment was used in five (45.5%) patients. Specifically, we observed a significant increase in both ARA and LAMD comparing baseline and post-treatment measurements (p < 0.001). Quality of life scale scores at baseline and after treatment demonstrated a significant improvement in both tools (p < 0.0001). Conclusions: Flat Magnetic Stimulation, with or without adjuvant pharmacological treatment, demonstrated safety and efficacy in reducing pelvic floor hypertonicity, resulting in improvement in symptoms' severity and sonographic parameters of muscular spasm.