I was sitting on this chair thats attached to a cane and it broke on me, and my right knee moved all the way back, now its sore, did I mess it up?

Sprain. This is a sprain type injury. However if swelling develops, an internal knee joint injury like torn cartilage or ligament is possible. At this time I recommend cold applications for 48 hours along with rest,elevation of your leg and,if you can take them, anti-inflammatory medications like Advil or Aleve(with food). If you develop severe pain and swelling, consult an orthopedic surgeon.