This helps calm the effects of allergy drainage, which can upset the stomach and cause a sore throat. The other thing I do is take 1200 mg.
guaifenesin (Mucinex or generic), once
in the morning and again at bedtime. This thins mucus so that it *will* drain, also allowing the throat more moisture. I have also come across mention of people using guaifenesin in their treatment of fibromyalgia (https://www.drugs.com/comments/guaifenesin/for-fibromyalgia.html).