Thanks for asking the query,
Dull type of pain near the left jaw and ear can be due to Temporomandibular joint disorders , neuralgias, sinusitis
I would suggest you to get a thorough clinical examination done by an ENT specialist
and Oral and Maxillofacial Surgeon. Take an OPG radiograph to look for the TMJ
TMJ disfunction can also cause pain around the ear, tenderness in the jaw,difficulty in mouth opening and pain on chewing.
A detailed clinical evaluation by your Doctor is needed to confirm your cause and to plan appropriate treatment.
Hope this helps out.