The term tonsillitis means that the tonsils are inflamed. Usually this refers to enlarged, pussy tonsils. The diagram shows where the tonsils are. Tonsillitis can occur with many causes of sore throat. Pus on the tonsils is not a sign of bacterial infection.
Mononucleosis can cause a severe tonsillitis.
The typical cold may cause a sore throat during any part of the illness. Colds often begin with a scratchy throat up behind the nose. Severe coughing may also result in a sore throat just from the force of the cough. People with stuffed noses often wake up with sore throats because they breathe dry air through their mouths all night. A humidifier is very helpful for this symptom.