Breast pains fatter breastfeeding

I breastfed my son for 13 months when he decided to wean himself. I decreased feelings and my milk mostly dried up. Fast forward to almost six months later, I still have letdown sensations except at the end, there's what feels like an intense shock and pain to my breasts. It happens several times a day and my milk has never completely dried up as in, if I tried, I could express a few drops and I occasionally leak. My breasts are constantly tender and sore. Has anyone experienced anything like this? I just can't understand why I'm still having this problem after so long. Any experience or thoughts would be helpful. Thanks!