Did they take an x-ray to see if there may be a root tip or other possible broken piece of tooth in the gum area?
Was the denture adjusted at all to make sure the fit is still proper? It may be rubbing a sore spot and causing an irritation in the area
In April, I visited a maxillo facial surgeon who saw a sharp bone protrusion that may have been the problem. The removal did not fix the problem. The denture was adjusted and checked for proper fit.
As I said, I was able to live with it and took ibuprofen to stop the pain until a few weeks ago, when I had severe pain and a few sleepless nights. I have had to stop wearing the denture. Even so I get bouts of pain from physical activity such as lifting, even playing the violin, or even eating without the dentures in place. The pain is less severe than that associated with wearing the dentures and goes away after a couple of hours of treatment with ice and ibuprofen. It is not entirely predictable and a I have put in a day of heavy hiking without a problem.
I am going to make n appointment with the maxillo facial specialist again to see if he can figure out what is wrong and find a fix.