Lump in armpit

[horsebiscuit]

Woke up this morning with a painful lump in my armpit. Could this be a blocked duct? I've had them before but in my boob not armpit.
As a bit of background, I'm bf 8 month old DD2 and she had her first bottle of formula last night as I went out dancing in an underwired non nursing bra if that's relevant to Queen if that's relevant.
Thanks in advance if anyone can help with my total lack of understanding of basic physiology.

I would try to see a doctor ASAP. It could be a whole range of things.

I've been bf for 13 weeks so far and in that time I've had a couple of lumps in the armpit. I was v worried the first time, but I had a go at massaging gently when feeding and they gradually went away over a few day period.
Obviously you will probably want to get it checked with the doc but that was my experience!