Could you tell me why my jaw recently gets locked after clicking and poping for a month? it opens only 2 and half fingers wide?

Closed lock: You have closed lock, a condition where there is obstruction to opening in the joint.As joints go, the TMJ and its disk are very mobile. Many patients disks are out of proper position from stretched attachments . What you feel is the jaw bone sliding over the displaced disk, with a "catch" often with a popping noise as you open. The management is usually conservative unless pain or decreased funct.

TMJ Disc Displaced: This condition is characterized by displacement of the disc on closing followed by a failure to reduce the disc on opening and cause the jaw lock. The disorder is sometimes referred as "closed lock.". Initial therapy should be directed toward reducing the disc displacement through a manual mobilization. Rec.: see orofacial pain specialist for conservative solution. Very common and treatable.