when the liver is overwhelmed it backs up into the neck and shoulders. this is part of what ear wax is. when your shoulders and neck are sore, it is toxins. this is why stress can cause this because stress produces lots of acids and such.
my suggestion, beyond learning to cope with stress and eating right, is to use hot baths and a good lymph massage. get the lymph moving - cold sitz bath, rebounder, etc.