Why are my nipples sore after breastfeeding for 7 weeks? how can i get rid of the soreness?

Many possibilities: I suggest working with a qualified IBCLC (International Board Certified Lactation Consultant) to figure out what the cause is for your situation. Find one near you at http://www.ilca.org/ Then you can address the cause to help with the soreness. Causes could range from latch and positioning, to a tongue-tied baby, to thrush...impossible to say without observing a feed and examining mom & baby.