Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern..
As per your complain it seems that along with breakage of the jaw there has also been jaw joint dislocation and you are right as it seems that while replacing the lower jaw t has been placed too far back and not articulating properly at the lower part of the skull..
There can also be forward[ anterior] displacement of articular disc that is a soft cushion present between the two bony ends of the joint..
You need to get treated and although many a times surgery is not needed..
You should consult a trained oral surgeon and get evaluated and he can advise you oral splints, corrective orthodontic appliances [ functional jaw orthodontic splints] and physiotherapy
to improve the condition..
In case if all these does not work then surgical correction can be done..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.