Hard, red, shiny, painless acne need help diagnose

[learnhelp11237]

So, I have had these chest 'acne' bumps for a long time. Each one grows and stays, not a single one had receeded, at firs they look like normal chest acne, then they grow bigger and bigger, very slowly. Had them for at least 2 years now on chest and back. Face is clear of acne (mostly)
the acne is permanent, never receeds, but are never painful, even when squeezed, no itch, nothing, but they are red. there are around 40, small and large, the largest ones are around 1 cm across, mostly symetrical, some are more oval-like. They are also very raised. The thing is, all dermatologists I have seen have dismissed them as cystic acne, but that is very painful and lasts months top, these feel like long-healed scars, and have lasted for years. I do keloid scar.
-generally, they just feel like keloid scars when poked, no inherint pain/itch
no topical treatment works, and antibiotics have no effect, and no irritation, meaning that no serious bacterial infection.
-jabbed one with a needle and blood came out, not a single bit of pus, (it was more to the side and not direct, so I may have missed pus, but they are not full of it.)
-no proper diagnosis reached, and these things grow progressively, from tiny spots 1 mm across, slowly to larger sizes.
-no alterior symptoms, not likely to be skin cancer.
-is it even acne? but I have yet to recive a proper diagnosis, please help.