Does twisting your knee to the left or right with pain indicate a medial meniscus tear? If I move my knee that way the pain is unbearable

Sounds like tear. What you are describing in orthopedics is called the apley's test and is characteristic of a meniscus tear. Similar pain can occur if you have some arthritis in this compartment of the joint. Agree that you should see an orthopedic surgeon particularly if catching, swelling and/or giving way is occurring. They will consider an MRI to better define the pathology.
Meniscus tear. Consult a sports medicine doctor or an orthopedist. It sounds like a damaged meniscus.

Related Questions

My knee hurts to pedal a stationary bike. I can't go forward I can only go backwards. I do have a medial meniscus tear? Help

See ortho doc. You answered your own question with the diagnosed menus all tear. This can be helped with arthroscopic surgery. Your bicycle is loading the joint, creating pressure on the tear and causing pain. Topical prescription and oral NSAIDS will reduce the inflammation. Using a reclining bike that shifts your weight will allow you to pedal a lot further with outs generating this pain. Read more...