Hi Naravahanata. I agree that it is most likely normal detox symptoms, and on a known problem you periodically suffer from it seems. You can never tell when these symptoms will pop up, apparently if we fast to 'completion' everything gets done in one hit as a rule. If we do many shorter fasts then we will probably have many different detox symptoms depending on what is left in the body to expel. One of my chronic problems is sinus related and I often have a lot of mucous in the head and throat during fasting. Luckily it is a different type of sinus problem while fasting- runny noses and probably excretions from the chest- but no headaches or trouble breathing due to the congestion as all the mucous is on it's way out of the body.
I must admit the razor blades in the throat is a new one on me, I hope it doesn't last too long for you.
Good luck getting back to your invincible fasting! :)