Welcome in H.C.M.
I have gone through your query regarding lump over hinge of jaw, giving rise to pain on eating, speaking and all jaw movement.
Here I would like to say the common lump in this particular area are of-
1- Parotid lump.
2- Pre auricular lymphadenitis
of Temporomandibular joint.
All these lumps when appears as acute are always painfull and most of the time pain is felt in ear with all movements of jaw. On the other hand if lump is chronic than usually pain is no more felt by patient.
To diagnose it and to manage these few basic investigations are necessary-
1- X-Ray OPG (orthopentogram)
2- Ultrasonic study of lump.
3- FNAC from lump.
Above investigations will help in reaching to correct diagnosis and accordingly you may consult specialist for curative treatment.