Right breast hurting/sore on/off 12 days before period. Have had pain in past but not this early before period. Normal?

Fibrocystic breast disease. Sounds like fibrocystic disease, and the variation in the duration of tenderness is related to your hormonal changes.
Can be normal. Hormonal breast swelling ; discomfort is common. Fibrocystic breast condition can be associated with more breast discomfort. Use of hormone medications can also affect breast discomfort. See your doctor for an exam if this persists.