I'm not sure if I'm understanding this right, but correct me if I'm wrong: you say you're 14?
If that's true, you are growing and your breasts will hurt. Gah- mine hurt on a regular basis until I was 16, and then it hurt when I went on birth control (more hormones affecting my breasts). So, if you are growing...it's going to hurt a little bit.
I don't think it has anything to do with you wearing a bra regularly. The only reason I would think that is if you had the wrong size (which is a very common mistake by women). If you feel it's your bra, perhaps looking into a new size. They aren't supposed to choke your body; they need to offer support, but not hurt you. When I went into Victoria's Secret, I had my bra size checked (took 15 seconds, with my clothes on) and surprised at the size. I had been wearing the wrong size, and finding the correct size relieved me of a lot of pain.
Maybe I should clarify- is this a sharp pain in your actual breast? dull pain in the breast? dull back pain?