Do restrict your mouth opening while yawning and do not stuff your mouth with lots of food. Mouth opening at times is involuntary and intentional effort of restricting it is an effort from your side. At an early of 22 its better to get it examined and if deemed necessry an addional MRI would help. Be cautious and not negligent.

Hi there ...you should consult a oral surgeon or oral medicine specialist for proper diagnosis with x-rays ...ASAP. As home care measures, support your jaws while yawning, talk less and don't try to open your mouth wide... Take care ..!!

You need to get a thorough check up done by a dentist,who might recommend some x rays to be taken and referral to a specialist if required.

Hi..you need an orthodontic correction. It can be solved if doctor is expert in treatments of TMJ disorder. Regards

You might undergone any injury on chin ... it's better to consult a dentist near by you...till then don't try to open your mouth too much.....n support it while yawning n during cough....