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Most often a sore throat is due to increased mucus production. Since your's seems to come at the same time, it may be due to allergies. Does this occur after you are in bed? If so do you have a pet that gets on your pillow? It would be important to try to figure out if there is something that is triggering an allergy, and then remove it or in some way deal with it. For example, if it was a pet, placing another cover over the pillow area and removing it before sleeping would help. An air purifier may also help, if there seems to be an allergy problem at home. Of course antihistamines can be taken as well.
Please reply with your thoughts, or when this occurs if you have questions or more details.
Besides removing the allergen or taking medicine, you may want to consider using a neti pot every day or so. It is easier than it looks. The saline (salt water) rinses out the pollen, dander, dust, mold etc., and can be quite helpful, and prevent you from getting an infection that can occur if the the sinuses don't drain well.