Objectives: This study aimed to investigate the impact of scrotal pain on venous diameter and reflux duration in varicocele, and to assess the predictive value of ultrasonographic findings for varicocele grading. Methods: Fifty-two symptomatic patients with left-sided varicocele, presenting with infertility or scrotal pain, were prospectively evaluated. Grading was based on physical examination. Visual Analog Scale (VAS) scores, venous diameters, and reflux durations were measured using scrotal color Doppler ultrasonography (CDUS) both during active pain and after pain had markedly subsided or resolved. Results: After pain resolution, venous diameters significantly decreased in both resting and Valsalva states (p < 0.001). In grade-specific analysis, this reduction was significant only in grade II varicocele (rest: p = 0.004; Valsalva: p = 0.026). Reflux durations also significantly decreased after pain relief in all varicocele grades, both at rest and during Valsalva (p < 0.001 for all, except G3 Valsalva: p = 0.001). Ultrasonographic parameters during the pain-present state showed better discrimination for detecting grade I varicocele (AUC: 0.88), while the pain-free state provided better diagnostic accuracy for grade III varicocele (AUC: 0.69). Combining measurements from both conditions further improved predictive accuracy, especially for grade III varicocele (AUC: 0.77). Conclusions: Scrotal pain significantly influences scrotal CDUS findings in patients with varicocele, leading to measurable differences in venous diameter and reflux duration between pain-present and pain-free states. Therefore, consideration of symptom status when interpreting scrotal CDUS results may improve diagnostic accuracy and support more informed clinical decision-making.