Hi J.! please go to the dr asap! not to scare you, but I had the same thing! I had this pain underneath my breast and I couldn't stand using a bra, it hurst and I didn't feel or see anything on my breast, and I waited 7 months (no joke). and then it kept progressing inside my breast that pain. I finally spoke to my dr and he said might be the muscle, blah, blah, gave me some muscle relaxes pills, didn't work at all! so one day I got tired of it and I told him I wanted a mammogram asap, he did and also an ultrasound. They found some nodules on the right breast (weird cause both hurt but the left breast it was worst), and to check back in 6 months. But I asked the nurse dr what can I take for the pain, she was reluctant and said tylenol..yup I got so upset, that thank god my ins doesn't require a referral I went directly to a breast center, (this was 3 weeks ago that I saw this specialist) the best thing I could have ever done, I took my results in and she did another ultrasound, found I had fibrocystic cysts (and a lot of them) on both of the breast but one big one in the left one. Which she told me not to be scared but do have to monitor it more often and also gave me some antibiotic to see if the cysts can be decreased in size. So, I'm scheduled for another mammogram next week and see the specialist in the middle of august. And believe it or not i'm only 30 years old.
I tell you all this so you can see my story and not wait thinking it might go away or anything else....please go check yourself and if you don't feel right w/the results go further see another dr, get a 2nd opinion. That's the best you can do, believe me I feel so much better about my decision and the care I'm having now. good luck!