Sore Boobs Before Period?

How common is it? I've never gotten it before this month and last month. In my entire life. Last month I thought it was a pregnancy sign but alas. The fact that they're sore again has me already feeling like I'm out. But for curiosity sake, how many of you feel this? They are DISGUSTINGLY painful. Like I actually feel like taking my bra off at work kind of sore.