BOYS, WHY DONT I GUYS APPROACH ME, YET THEY TELL OTHERS IM CUTE, OR TRY TO CHAT ME ONLINE, STARE....ETC...?=/?

really don't know whats wrong with me. IM 21 years old & I know guys think i'm cute/hott/whatever, because I have friends who tell me "so & so thinks your cute but is shy to talk to you" or "my friend so & so saw your pics and wants to meet you". I have had 2 boyfriends, but both were basically set ups. The first one my friend set us up cuz she was friends with him too and he liked me...so she introduced us, and the 2nd one was also pretty much done the same way except we started talking on fb through a mutual friend & then met. I have NEVER had a guy actually approach me & introduce himself to me or ask me out or anything. I barely even have any guy friends, maybe just 1-2, & the other guys I met in my class ended up just being "HI' "BYE" friends...idk why. I still have contact with my ex bfs friends tho(i knew them b4 i knew him) and they all are, ALL OVER one of my friends who they met ONCE, and she is younger than them too, they have all asked her out atleast once. Its kind of frustrated though knowing that there are guys who like me or find me attractive yet never are able to approach me themselves, and IM a shyy one so no i can't approach them myselves ill be too embarrassed. SO what do you think im doing wrong & what can i change???