Affirming breast pain

So yeah I was playing and joking around with my niece and at one moment she just hit me (as kids sometimes can do) on my left breastgrowth (I wouldn't say boob yet but yeah) and that PAIN(!), I mean c'mon... it didn't wear off until approx 20 minutes later. It was like being hit on the male genitalia. I told her previously that I was a bit sore on the chest. And she was like: "i'm sorry but it wasnt really that Hard". Me gasping with pain: " yeah I know but as I said, i'm a bit sore there". Everyone else knows that i'm trans mtf and on HRT but I havent told my niece and nephews yet, they are all under ten years old. The parents will tell them eventually though. But yeah just wanted to share the affirming experience. :)