I guarantee you that you will enjoy it. I haven't had top surgery yet, but I have always had pretty small boobs. I have no back pain, I can sleep on my stomach, I rarely wear bras 'cause I just don't need them, I walk around my house with no shirt and I can't feel my breasts (in the sense that there is no weight on my chest), they don't go to the side when I lie on my back, I have no seat belt issues... the list goes on and on.
And one that won't apply once you've had surgery but is good for me now is that when I wear my binder it's no tighter on my chest that a sports bra yet makes me totally flat, therefore causing no pain (though I find it annoying because I have never really worn bras and hate anything around my rib cage). Also, I can not bind if I wear a sweatshirt or a sleeveless hoodie shirt or anything else that's thick material and I look totally flat. Sorry, got a little off topic there!
My point being, I am pretty sure that you will be super happy once you've had top surgery. There are SO many advantages to having a small chest. One of my styling clients also just had a double mastectomy and hasn't had reconstruction yet, but she says she plans on getting an A cup (she was a D before!). Even back when I was living life super femme, you couldn't have paid me to get a boob job--too many disadvantages just to look "sexier". Not that there is anything wrong with people wanting to do that, but in my experience being small/flat is fantastic! So no worries, my friend, you're gonna love it!