Painful!

So, as I write this.. I am currently wearing a lovely sports bra.

For the past week, I have had intense pain mainly in my right breast. It is normally on the right side of the breast and sometimes moves to the underside.

I do get pain in both boobs but the most painful is my right one which so happens to be my bigger boobs. (I have asymmetrical breasts)

I have noticed that my breasts are sometimes hard in places, this usually goes away after I take a normal bra off before I shower.

I am due on today (not shown yet) so I know this could be a leading factor as too why I have painful breasts.

But this is a continuing problem, before and after any period I have.

Because of the pain, I have had to resort to wearing a sports bra with zero padding as any sort of pressure on my boob just kills me!

I have also read that caffeine intake could be a factor as well, but i only have 1 cup of coffee a day and I sometimes don't have anything at all.

Has anybody got any ideas what this could mean or be??