Mouth problem

[Tinkerpuss]

My 16 year old cat had some teeth out last month.and since then has been having a problem which causes her to keep pawing her mouth. I took her back to the vet who had a look and said she had a couple of sores in her mouth and gave me antibiotics and a painkiller.
This did not seem to help so I went to the vet again (bank balance going down rapidly) who could not see anything. gave me painkillers and said that if the problem continued she would have to have an anaesthetic for them to investigate (overdraft on the horizon).
I have a theory that her jaw may be clicking out of place and the battle she has is the discomfort she feels until she can get it back again. At all other times she is quite happy and does not appear to be in pain.
Obviously I intend to take her back to the vet but has anyone come across this problem?