Sore boobs middle of cycle?

I normally have sore bobs the week before my period religiously! At the moment however my period isn't due until 10th march (give or take a day) and I'm wondering why my boobs are so sore, as my last period ended 5th feb.. I read that people get sore boobs when they ovulate however I've never had that before.. Is it something that can start whenever? Even if I've never had it before during ovulation?