Could biting my tongue cause a sore neck (not throat)?
A canker sore is like a wound, so it can get infected. There are glands in your neck (lymph nodes) that release antibodies to fight infection. In my experience, it gets sore similar to the feeling of a stiff neck or when I slept the wrong way, when it is overworked. Once for a mysterious infection, I had to take antibiotics for two weeks and my neck felt sore all the time. Maybe your lymph node is just overworked from fighting off an infection in your canker sore. Afterall, the mouth is a pretty nasty place. Ask your doctor or dentist to prescribe you something.
