Bob & Laurie, Welcome to the site. Sorry you had to find us and am glad to hear you finished rad treatments. I know it is tough for you now. Just keep in mind that this is as bad as it gets. In a few weeks, you will notice an improvement and it just keeps getting better from there. You just have to get through this time when it is tough, but you will, we all have. So welcome to the club nobody wants to join.
As far as the phlegm goes, it is part of the experience. Radiation is the treatment that keeps on giving and you just have to get through it. I spent many a time vomiting into the toilet, just as you are, trying to clear that stuff from my throat. I couldn't talk or eat or even swallow my own saliva. I had a peg also and that kept me alive. But you will get through it just hang in there.
Some of the other members on the board have tried some things to help the phlegm, but when I asked my rad doctor, he just raised his shoulders and told me there was nothing they could do. So I just hung in there and in about 3 weeks it went away. At least most of it did. I still have some issues with it, but it is 95% better than in the first 3 weeks. My doctor also told me that it can take up to 2 years for all of the side effects to settle down and for me to be in the final condition of post treatment, so I am still "on the mend" as they say.
Hope this helps a little. Will add you to my prayers.