Hello and welcome to hcm,
As you mentioned,usually yoga cannot cause any kind of jaw pain.
This can be occured due to-
Muscle stretching/twitching during exercises.
Dental infections underlying.
An x-ray of the area will help to evaluate the cause of jaw-ache.
Usually associated causes can be-
due to impacted wisdom teeth.
Deep dental caries
progressed into periapical area.
Traumatic injury due to fracture of jaws.
Please do visit a dentist
and get further treatments based on the clinical examination.
Meanwhile,maintain good oral hygiene.
Avoid heavy exercises which can harm your physical health.