Sounds to me you either just feel empty for some reason or are a pathological thrill seeker - if the latter it's healthier to take up an extreme sport to get your kicks, if the former you have to look inside yourself and find out why you see no purpose for yourself in life.
I get part of the attraction ; I didn't wanna be a junkie exactly but once I ended up as one, there was a single-focus simplicity to that life which in a fucked-up way I miss.
I have a mind like a washing machine that just turns over bad shit constantly, I find the complexities and responsibilities of life often overwhelming, and in that existence there was none of that. I didn't have any identity crises, I knew what I was and so did everyone in the streets who looked at me with instant contempt. I didn't worry about what I was gonna do with my life, I knew what I was gonna do from the moment I woke up to the moment I went to bed, and that was hustle money for heroin, score heroin, do heroin.
.... There's better ways to waste your time on this planet.
PS you got the *opiate-naive* thing the wrong way round. If it didn't do what you were looking for when you hadn't had opiates before, don't hope for any more from it. That's the best it's gonna get. Bloody hell 25 mg of codeine smacked me sideways, way back.