Thanks for asking the query,
Pain in the jaw and difficulty in mouth opening can be due to Temporomandibular Joint Disorders, jaw injury, bruxism
can make one suseptible to such disorders.
Get a clinical evaluation done by a Oral and Maxillofacial Surgeon.
Take an OPG x-ray, depending upon which treatment will be decided.
Pain in the neck can (radiating pain
) be due to dental problems.
Apply cold packs externally over the affected area.
Eat soft diet
Maintain a good oral hygiene
, use antiseptic mouthwash gargles twice daily.
Hope this helps out.