Hi Sherri and welcome to the board! I'm on vacation at the moment and just saw your post, or I would have responded sooner.
The guai will exacerbate any FM symptoms you had before starting it and sometimes new ones you haven't had before will show up. Swollen glands, sore throats, sinus flare-ups, weird pain in any and all parts of your body and so on, are very common reactions to the initial "cycling" you will do on guaifenesin. But, just to be sure, it would be good to check it out with your dr. anyway.
By now, it may have settled down by itself, if it is due to guai cycling. During the first week or so on the guaifenesin, you will experience a lot of symptoms at first, and then it will settle down for you, and "work" (detox/pull out phosphates) on different areas in your body one at a time. But don't be surprised if this heaviness in your throat reappears from time to time either.
What dose are you taking? Hope you are feeling better by now. Sorry that I wasn't around to respond sooner!
Val |