I forgot to tell you that I've been having a bit of preserved ginger when the tingly tongue was annoying me and it seems to help. I kept the ginger on my tongue as long as possible. Ginger is very good for an upset stomach, too. Ginger tea, or grated fresh ginger would do the trick, too.
I've re-read the thread and also Googled about pine nuts, and I bought a pesto salad from the supermarket a few days ago, which would have had pine nuts in it, so that may be the culprit for my bout of soapy-itis. I'll be making my own pesto and checking the labels on the pine nuts from now on. (Being an imaginative cynic, I'm wondering whether the Chinese pine nuts have been soaked in pine scented disinfectant (Pine O Cleen) or pine-scent chemical to "enhance" the flavour - sorry, just a thought!)