Strange pink stains on my shirt (armpit area)

Okay, so I put my shirt through the washer (and dryer, blahblahblah) but when it came out, the armpit area on the sleeves were pink! I have no idea why. is this common at all? and how can I get rid of the pink stains?

I think they are sweat stains. Mine do that to but they arnt pink they are more of a dark color. after you put it in the dryer though its not going to come out.

maybe your sweat reacted with the dye in some piece of clohing, or it reacted with the washing powder

ooo thats bad. o_o
is there a way to get it out though???

Well depending on the color of your shirt,You might be able to bleach it out.

I think they are stains from a deodorant or antiperspirant. Have you changed brands?