Thanks for the posting your query.
You are most likely suffering from acute upper respiratory tract
infection; mostly viral in nature.
These infection may involve pharynx and tonsils and may cause secondary bacterial infection.
Presence of sore throat
of mouth and ulcer suggests the diagnosis.
You should consult with internal medicine specialist and should go for thorough check up.
You should take cough
suppressants, decongestants, throat soothing and antipyretics.
You should also perform gargles three times in a day.
Dr. Mayank Bhargava