I have no special knowledge of dentures or AS pain threshold. I'll state my opinion any way. My opinion is that the AS low pain threshold could be a factor, but it's more likely that the denture is not fitting well in your gum. I think something like that happens very commonly with any dental procedure. I have had crowns and fillings made for my teeth, but they often had to be adjusted a little because the shape was not exactly right and I felt pain/discomfort. I think you should just mention it to your dentist and I'm sure they will try to adjust it for you. You might also need some time to get used to it. I hope you get it sorted soon. My mum had a similar problem for a few months recently and it affected her joy of eating so much. In a long term it could affect your health in general, too. I'm so relieved that now her tooth is back to normal.