Hi, earlier this week I started experiencing a sore throat, and about 2-3 days ago I noticed a sore at the back of my throat (canker sore). The pain has been horrible, to the point where I can t sleep because breathing and swallowing hurt too much. And accompanying the sore has been symptoms that include: tiredness, a hacking cough, stuffed nose/clogged nose, and diarrhea. I m worried that the canker sore might be a sign of an infection.