I just worked out yesterday and I didn't wear a sports bra, or any bra at all. And now today my left boob hurts a lot anytime I move, cough, or take deep breaths. I've noticed this pain before in my boob but never really thought much of it cause it wasn't too bad. But I'm wondering is it just worse cause I didn't have a bra on yesterday? Or should I be worried about possible breast cancer? I felt and I didn't find any lumps, but I've read that there aren't always lumps... please help, I'm freaking out...