Scrapping noise coming from the passenger side

I don't know the year of it but it's the older bodystyle so I'm gonna say around a '95?... I'm not sure what this is, but when driving at any speed there's this scrapping sound coming from the passenger side on the back. The faster you go the faster you hear it. It's not a constant noise, it's sounds more like something is turning and it's hitting or scrapping on something, so when you go faster it's doing it faster.... Any ideas as to what it might be ?... Axle bearing maybe ?

I don't know too much about the truck besides the owner thinking it needs a new rear axle and brakes.

What wheels do you have? Seriously.

I have the steel OEM wheels on mine that are forever collecting rocks for what ever reason, they get lodged between the wheel and the rotor and it sounds like a scrapping noise. That you can hear more and more as the speed increases, and/or if you turn a corner putting more lean on that particular wheel. Seems to be the backwheels that are more effected.