BACKGROUND: Shoulder pain is a frequent and clinically relevant nonmotor symptom in Parkinson's disease (PD). Although suprascapular nerve block and pulsed radiofrequency (PRF) are used effectively for chronic shoulder pain in the general population, their therapeutic effects in patients with PD have not been clearly established. OBJECTIVE: To assess the clinical efficacy of suprascapular nerve block combined with PRF in PD-related shoulder pain and its association with rigidity severity. METHODS: This prospective, matched cohort study included 20 patients with PD and 20 age- and sex-matched controls with chronic shoulder pain consistent with subacromial pain syndrome. All participants underwent ultrasound-guided suprascapular nerve block combined with PRF. Pain intensity was assessed using the Numeric Rating Scale (NRS), and shoulder-related pain and disability were evaluated using the Shoulder Pain and Disability Index (SPADI). Outcomes were recorded at baseline and during follow-up. Associations between rigidity severity, levodopa equivalent daily dose (LEDD), and changes in clinical outcomes were analyzed using Spearman and partial correlation analyses. RESULTS: Both groups demonstrated significant reductions in NRS and SPADI scores following the intervention (all p < 0.01). Although overall pain and disability improved, SPADI pain scores remained significantly higher in the PD group at follow-up. Greater rigidity severity was consistently associated with reduced improvement in pain- and disability-related outcomes, ranging from trend-level to statistically significant correlations. CONCLUSION: Suprascapular nerve block combined with PRF provides meaningful pain relief in patients with PD and chronic shoulder pain. However, greater rigidity severity appears to limit clinical improvement, suggesting that disease-specific motor features play an important role in shaping pain burden and response to peripheral interventions in PD. These findings highlight the need for multimodal pain management strategies addressing both peripheral and central disease-related factors.