You're right around a growth spurt, so if she's feeding more often and for longer - this will have the effect of upping your supply in a couple of days as your breasts adjust to the new demands - you might well feel some soreness. Massage with hot compresses (I used a sock filled with rice that I heated in the microwave), or use cool packs to soothe irritated nipples as needed.
Keep an eye out for thrush or mastitis, but keep feeding on demand for now; odds are that things will resolve within the next few days. If the discomfort goes all the way to pain, check with your doctor/HV.