What Causes Sore Breast With Liquid Discharge While Squeezing?

Hi. Last month for the first time . i squeezed my nipple and a little bit of clear liquid came out. i was late 10 days and got my period on the 16th. and 3 & 6 days late i took a prenancy test and it came out negative. this first week of this month my breat became a lil sore . and everytime i squeeze a lil still clear liquid is coming out. this has never happened to me before. Could i be pregnant?