Can i have a torn sl ligament even if mt mri is normal?

Yes and no: you could have a bruised or stretched or injured ACL ligament with normal MRI if there is any tear the MRI will showed it if you are having pain make sure you see a knee specialist

Ligamentous tear: I assume you are talking about the scaphulolunate ligament in the wrist. An MRI is not absolute, but is usually pretty sensitive to pick up a ligamentous tear. A significant tear would result in instability of the wrist. I would continue to follow the guidance of your orthopedic surgeon and physical therapist regarding appropriate treatment.