Sounds weird but why?

GMC

Why do I have 1 sensitive (not hurting just sensitive) boob well nipple really? Like why I’ve never had this why only the right one? Left boob is itchy like wtf? Like was my right boob like left one was itchy last week I felt left out. Then left one like damn now I’m left out itchy again. What is happening?! I keep also thinking af is coming but nope just a little cm there. Af is due Monday.