It is quite normal for teeth to feel tender or sore for a couple of days after any new orthodontic appliance is placed or after one of your routine adjustment appointments.  This is usually a sign that the appliance is working and the teeth are moving!

Soft foods and and some Panadol or Nurofen should provide relief and usually after 2-3 days the discomfort will settle.  

Often a new appliance will rub on the cheeks, tongue or gums and if so, please use some of the orthodontic wax provided to help.  This is especially helpful in the first week or two.  If the appliance rubs or causes any ulcers just roll up a piece of wax, dry the area that’s causing the sore spot with a tissue and push some wax over it.  To help the healing process rinse your mouth out with warm salty water as well.