Hey ,

There can be several reasons why your throat is sore in the morning. You are right, airconditioners and mouth breathing can cause a sore throat in the morning! Here are some other reasons why people can experience a sore throat:
• Dehydration
If you are not drinking enough water during the day, you can experience a dry or sore throat in the morning. Water is necessary for the production of saliva. During the night saliva production is less than during the day. This is why you might experience a dry and sore throat in the morning.
• Dry air
When the air in your bedroom is too dry this can lead to a sore throat in the morning as well. In the colder seasons, the air can get dryer as well. I don’t think you have to worry about colder seasons, but I like to be thorough.
• Allergies
Allergies to dust, mold, pollen and pets can cause a sore throat as well. Other complaints that can come with allergies are watery eyes, a runny nose, sneezing and coughing
• Air pollution
Cigarette smoke, smog from cars, but also candles and other air pollutants can cause a sore throat in the morning. 
• GERD
Do you experience acid reflux? With acid reflux, you could experience a sore throat in the morning as well. Other complaints with GERD are chest pain that radiates to the neck and throat also called heartburn.
• Bacterial & Viral infections
Do you experience also other complaints like difficulty swallowing, headache, fever or body aches? Some forms of infection could cause a sore throat in the morning as well.

Does something resonate with you?