Could u be mistaking the tiny hairs on your chest for blackheads?
I have some fair hair on my chest, which is just normal, I mean, we have hair everywhere! Sometimes if u look too closely at it, and analyse, u could maybe mistake it for blackheads.
If they are blackheads, I'm not sure what u could do sorry! Maybe talk to your doctor?
As for the ones on your back....again, ask the doctor.
Great beauty and virtue rarely dwell together.