Grade 1 acl tear will not be the cause of pain. There might be some other pathology may be a meniscus tear or cartilage damage or not adequate rest or weakness of your muscles which might be the real cause of pain.
Next Steps
Get yourself reevaluated. Repeat mri not necessary.
Health Tips
Do your Quadriceps and hamstring strengthening exercises. No cross legged sitting or climbing stairs. Avoid terminal flexion of knees