Thanks for asking the query,
Stiff jaw, clicking and popping jaw while opening and closing of mandible occurs due TMJ
I would suggest you to visit to an Oral and Maxillofacial Surgeon and get a checkup done, take an x-ray to look for the condition of the jaw.
Take semisolid diet.
Take mucle relaxants along with pain killers.
Take a semisolid diet.
Apply moist heat towels externally over both the jaws.
Hope this helps out.