Jaw lock for 2 days?

Closed lock: Probably an issue referred to as a TMJ closed lock. This is not dangerous and usually is a result of inflammation resulting from chronic bruxism (tooth grinding) while you are asleep at night. It will likely resolve on it's own, but may require a visit to an oral surgeon. You'll want to consult with your dentist for splint therapy to avoid this in the future and to protect your joints and teeth.

Oral Surgeon ASAP: If your jaw is locked closed for 2 days, you should see an oral surgeon to see if jaw manipulation is necessary. Ignoring this problem will likely lead to a chronic decrease in oral opening. Passage of time will slowly increase your opening, but not as much as before. See an oral surgeon.