On both breasts, but the sides near the armpits are extremely sore to touch. It has been like this for about 3 weeks now and it is not going. At first I thought it was muscle pain, but that is how it feels, but it should have gone by now. I then thought maybe it could be the bras that I am wearing, but that has made no difference. The rest of my breasts are fine, just the part closest to the armpit. I tried to forget about it, but it is not going. I can not lay on my front because it hurts. Is there any reason for this?

Are you doing some kind of repetitive thing (pushing to sit up or pushing to stand up) and using those muscles, but not realizing it? What about wire in your bras? Of course, the best way to find out is to make a doctor appointment and let him/her check that area and ask good questions.

Thanks for that. I think I should just see the doctor. I always thought it was my muscle, but am not 100% sure whether it is. Thanks again.