What Causes Enlargement Of Breasts And Clear Or Milky Discharge?

I noticed my breasts leaking clear or milky discharge a year or so after I had my first child. After becoming pregnant again I figured it would be attributed to that. My youngest is now 9, I stopped breastfeeding him at 8-9 months of age. My breasts still become enlarged and leak clear or milky discharge. More so when aroused. I do not have medical insurance nor the ability to see a doctor and wondered what I could do to stop this or how concerned I should be.