Can a doctor detect a meniscus tear just from a knee exam? i have had 2 exams, been told i have no probs, but knee still feels wrong. no pain.

Yes, if you: really have a torn meniscus, an orthopedic surgeon should be able to tell on physical exam alone. You might have another condition if you are having symptoms.

Exam not 100%!: A thorough knee exam will discern the vast majority of knee problems, BUT not all. You could have pain from an underlying "bone bruise" from an impact injury or a more superficial cartilage lesion. If you have given appropriate nonoperative treatment options ( rest, ice, Physical therapy, NSAIDs, etc.) a legitimate attempt, then an MRI may now be indicated