Not sure if I'm in the right area for this question but..

My son is a year an a half, i breastfeed him until he got about 9 months old, And here recently I've had this feeling in my boobs like I did when it was time to feed him when I was breastfeeding. Nothing ever comes out and it doesn get to a hurting point just get that feeling of like milk coming down I guess? I've never squeezed them or anything but did notice they seemed to feel a bit bigger after it happening. Has anyone has that happen? Is it a sign something else or just normal?