How long has this been going on? Is it a new thing, or something you've been having problems with for years?

I'm almost exactly your age & over the past 3 months or so I've been having breast soreness as well, although not 3 out of 4 weeks like you describe. They also don't hurt as much as you say yours do - they're a little tender, but it's not really painful to touch them. I also wear a 32C (after properly measuring and fitting myself, that is. I used to wear a 34A), coincidentally. I've assumed that mine were sore because they're growing. Not a lot, but enough to be noticeable to me and to my boyfriend. I'm also experiencing a new problem with breakouts on my chest, between my boobs, which I assumed were due to the same hormonal changes that are causing my breasts to grow.

Of course, all of this is just my speculation, and I'm not a medical professional or anything. Your breast soreness issue sounds much more severe than mine. Even though you don't want to bother your doctor, if it starts really interfering with your life or lasts for a really long period of time, maybe you should think about it.

I remember this happening to me, more than once. In my case it was always due to either breast growth, or wearing the wrong size bra. I went to more than one place to get measured, as well as measuring myself and discovered, that I thought I was a 34 (because who doesn't), I'm actually a 32. Wearing the right size bra made the pain go away.

I also took vitamin E, under the advice of my doctor, which helped, but nothing compared to the right bra.

As a woman you can expect breast growth throughout your life, and it is a good idea to get re-fitted every six months or so.

In my early 20s I was a 32B, and by 26 a 32C, now (27) I'm a 32DD (thanks to pregnancy)