I'm trying to say this without being mean because those who haven't seen it personally often don't know, but it sounds like you don't really have much experience with addicts. I can assure you that they don't care about cool or uncool like that.
However they get into it, peer pressure or to numb pain or just pain killer addiction, from them on it's about not feeling like shit, either because the drugs helped numb things or because as the original post mentioned the withdrawals suck.