Given all that happens to you when you go through a major surgery, I would be surprised if his throat wasn't sore. Who ever tubed me for anesthesia must have used something extra large and put it there with a hammer from the way my throat felt for weeks afterwards. While his doctors should be aware that he is experiencing pain in his tongue, even 4.5 year out now, my tongue gets sore all the time. It isn't cancer; it is the effects of xerostomia, and other residual issues that cause the discomfort. I'm trying to think if I've had a day without some sort of irritation or pain in my mouth since all this, and the answer is no. Let the doctors know. Make sure that it is in the records, have them monitor it, and continue to look for explanations. But it doesn't necessarily mean something really bad.