Constant breast tenderness on one side

kellybellybean

I nursed DD for 16 months and didn't have issues.  DS is 3 months old today, and I feel like I have had every issue in the book with him.  I've had clogged ducts upwards of 30 times, I've had mastitis, and I've had thrush.  Now I'm experiencing breast tenderness deep within one of my breasts.  It's not just when I'm nursing or just afterwards; it's constant.  I'm also experiencing nipple soreness on that side when he nurses.  I am so fed up with this constant battle to be comfortable.  Any idea what this could be and/or how to relieve the tenderness?  I just want to be pain-free and go about breastfeeding!