Knee Locking Post Arthroscopy

In October 2012, I had an arthroscopy done on my left knee for cysts that had formed in the patellar region. Also the MRI scans showed a small meniscal tear. During the surgery, my doc also did notchplasty, as the cavity was not wide enough for free movement. I was discharged after one day at the hospital and the doctor told me that after a week or two, I could resume my daily duties. Initially I noticed stiffness in the knee, but over a period of time, the stiffness subsided.
My problem is with the knee locking. It is about 4 months now, since my surgery, and I still find my left knee locking when extended fully. Even while standing, I find my left knee giving resistance to movement. With some difficulty, I can squat, but getting up from the squat position needs assistance of my both hands and the right knee. I saw my doctor about this problem. He asked me to get an Xray done, which showed nothing. So he concluded that the locking probably happened due to some loose scar tissues in the region. He said that it should dissolve on its own and the problem should go away by itself.

Prior to my surgery, I was an avid gym enthusiast, dancer. Now I find myself immobilized. My question is:

a) is knee locking a common complaint among arthroscopic patients and does it resolve on its own?
b) what can I do to improve my knee movement?
c) should I be worried that something is amiss, and see the doctor immediately?

I would advice you to consult an orthopedic surgeon if possible, the on who did the Arthroscopy. He can provide you with the cause and treatment of the problem.