What Causes Discharge From Nipples After Breastfeeding?

I am having some nipple discharge. Since I stopped breastfeeding in 2012 (I have 2 children) I have always had some amount of, what looked like, white milk clots in my nipples. They were never painful or leaky and always a mostly soft solid. I had a spontaneous liquid discharge from one breast about a year ago, but it was just a small amount, probably less than a single mL. I had a strange thought occur and decided to give my nipple a small squeeze and it easily produced a milky liquid discharge from both nipples - not more than a few drops, but there it was. What is going on? I am sick of weird symptoms that everyone says are PCOS but I can t seem to make better. Health Info: 36 yrs old, 250 lbs, anxiety & depression, high cholesterol, PCOS - all hormones normal including prolactin and thyroid as of 1 yr ago with no indication of actual cysts present. Diagnosis of PCOS was based on increased facial hair, mild male pattern hair loss which has ceased, and irregular periods. No fertility trouble - 2 normal and easy pregnancies. Most Antibiotics, rx level pain killers, and every birth control I have tried make me a sick, raving, looney. medications: metformin (insulin lvls have always been perfect and I am not the least bit diabetic), wellbutrin, zoloft, daily antihistamine. I have been on the metformin for 1 yr, the wellbutrin for 2 years, the zoloft for 6 months, and the antihistamine (over the counter 24 hour type) for 10ish years.