Objective To investigate the influence of transcutaneous electrical nerve stimulation (TENS) combined with rehabilitation training on pain severity, shoulder range of motion (ROM), and shoulder joint function in patients with shoulder joint pain. Methods A total of 78 patients with shoulder joint pain and pretreatment visual analogue scale (VAS) scores＜5 points who were treated in Hangzhou Xiaoshan District Traditional Chinese Medicine Hospital from January 2023 to December 2025 were enrolled. They were divided into the control group (n＝39) and the combined group (n＝39) according to different treatment plans. The control group received conventional rehabilitation training, while the combined group received additional TENS therapy on the basis of conventional rehabilitation training. Both groups were treated continuously for 8 weeks. The VAS scores, shoulder ROM, Japanese Orthopaedic Association (JOA) scores, and the grade of manual muscle test (MMT) of the related muscle groups of the affected shoulder joint between the two groups before and after treatment were compared. Results Before treatment, VAS scores were＜5 points in both groups and did not differ significantly between groups (P＞0.05). After treatment, VAS scores in both groups decreased significantly compared with those before treatment (all P＜0.05), whereas shoulder ROM, JOA scores, and MMT grade all improved significantly in both groups (all P＜0.05). Moreover, post-treatment values for all indicators were more favorable in the combined group than in the control group (all P＜0.05). Conclusion For patients with shoulder joint pain who have a VAS score of less than 5 points before treatment, TENS combined with rehabilitation training can effectively relieve shoulder joint pain, improve shoulder ROM, enhance shoulder joint function, and increase muscle strength of the affected shoulder-related muscle groups. Its clinical efficacy is superior to that of simple rehabilitation training.