hello thanks for consulting at hcm..1stly it could be autoimmune disorder like
rheumatoid arthritis since jaw joint , arm , toes ,
muscle pain,, 2ndly it could be sjogren's syndrome,, since
dry mouth, painful eyes etc,,,burning mouth,,,3rdly it could be due to infected teeth/
stomatitis,,hence to rule out one by one,, plz consult an endocrinologist/internal medicine and thn a oral medicine/ oral surgeon specialist,,hope it helps,,, tc