breast pain

So I went to my doctor about a month ago about my left breast hurting she felt both boobs and says she felt absolutely nothing, went on to say it was probably my hormones from where I was at in my cycle and because I carry my purse and son on that side, fast forward to a month later and my boob is still bothering me just when you touch it and mostly just on my nipple. I have no redness or lumps or dimpling of my skin. So my question is does any one know what else could be causing this?