For the first 4 months or so that I was taking Enbrel I got frequent sore throats. They were not like you are describing. Right around the time that I was to inject my throat would become raw and I would be convinced that I was getting sick but about a day after the injection it would go away. The doctor could never explain it and after 4 months or so it went away. I don't know if that helps but...
Stacey