Urticaria like spots on chest. have been there for years. not itchy or painful, same size and shape always. what could it be?

Not urticaria: Urticaria are very itchy spots fading away in a day often to be replaced with more hives that also last for a day. All allergic rashes itch. Rashes caused by other immune disorders blister or bruise. You likely have a benign disorder if it has been present for many years, has not changed & you are otherwise well. If you can afford a copay a hcp with dermatology expertise may help.