Why does sex hurt?

why when im tight sex hurts and I hurt alittle/??jw

You basically answered your own question - its because your tight. When your tight the muscles tighten up and it hurts a bit for something to go in there if you put in too much at once.

Tell your boyfriend to go slower and use lube. If it hurts tell him to stop. Pain should not be part of sex. (Unless you are into S&M, and then you have other problems.)
Enjoy life, and
Good Luck!!