This has to do with breasts as tiny as they are at this stage I keep SMASHING THEM GRARGAGH!!! there are other inconveniences associated with HRT that I'm appreciating now.
I had to reach across a workbench in a computer lab squished one of them on the corner of the table.
I catch myself on a door.
I pinch one on my backpack straps.
I walked into my room exhausted after a long day and an early start and I just flopped face first onto my mattress crushing them under me.
Double whammy carrying my shopping I'm no longer strong enough to carry my shopping bag with one arm. So I have to carry in a "bear hug" style infront of me and the bag rubs against my chest and rubs me red raw ugh!
I was playing "tennis" with house-mates involving pizza paddles and large foam footballs. Hehe

I know I'm mature! Many Ouchies in this.
1: you jump to hit the ball feeling a distinct 'Ow bounce.'
2: You get hit in the chest with the ball.
3a: You hard backhand swing bringing your arm sharply across your chest crushing yourself.
3b: Aggravated by the fact that I'm weaker now so I have to "Hard backhand swing" more.
They all came together when we lost our ball over the fence and I climbed onto the garage to see if I could see it huge number of limitations appeared showing that I'm not 'designed' for this anymore.
1: I used to be able to lift 120% my own body weight I can hardly lift myself anymore.
2: I of course catch my chest clambering onto the roof.
3: my skin is thinner softer and weaker now my hands were actually bleeding from the small cuts caused by the coarseness of the roof something that's not happened before.
The worst part of all is if you hurt your boobies they ALWAYS become erect It's like "no it's not a man begin kinky it's just a door!" and of course they then chafe against your clothes as you move. Thankfully there not large enough to be noticed yet so I can actually put my hand up my shirt and hold them when they are hurt which helps.
I don't think I'm an A-cup yet but is it really already time for me to get a bra?