Welcome Apple!
Army thats a blocked duct, apply heat and massage from top of breast down as firmly as you can tolerate and be sure to nurse every 2 hours, not nursing makes it worse even though it hurts when they latch. It will get better, just make sure you're emptying the breast as much as possible. Taking a hot shower and expressing in the shower I find works the best cause the heat numbs the massaging and expressing pain the best.