hello...this has happened to me too before...and i was not pregnant at the time....it is ur hormones believe it or not....especially if its right before ur period and if u r getting ready to have sex as in my case....it was more embarrassing than anything....hope this helps...
It could mean a few things, or nothing. Almost every female (especially one who has had children) will be able to express something when they squeeze their breasts. I'm not currently pregnant and can do this. It can also mean your hormones are higher than they should be, which would require additional testing to make sure nothing is wrong. It also of course could mean pregnancy.
See your doctor for blood work to test for pregnancy, as well as hormone testing to make sure nothing else is wrong.