I don't think it's related to wearing a new bra, because it happens on and off for a few weeks for a few days. I've had this in my right breast/armpit since early summer when I had a strange mild nasal/throat virus thing that lasted for weeks, but it won't completely go away.
There's no swelling and no other symptoms but the discomfort is quite noticeable whenever I move my right arm. Is it serious enough to see a Dr, do you think?