Breast feeding can hurt a little at first, your breast and nipples aren't used to it. The smoking should only be and minor factor compared to the benefits, besides baby will be in contact with your clothes anyway. While breastfeeding is one of the most natural things in the world, it does take some practice. If you have inverted or flat nipples, get breast shields. Make sure you have nursing pads so you don't leak through your shirt. If you want a lot of great information, I would recommend a book called, so that's what they're for.
Your hospital should have a free breast feeding class. I'd look into it