Quad stretch with extreme pain on the medial side of the knee. is this normal just had torn cartilage removed from the knee 7 days ago. in extreme pai?

This is not normal: and may be a number of different issues. Make an appointment to be seen by your health care provider tomorrow if possible. In the mean time ice the joint liberally.

Varies: Everyone's recovery is different, it could be simply related to postoperative swelling; but if the pain is extreme, I would just make sure your surgeon is aware just to make sure you are not having some type of peri operative complication.