I have had really bad yellow stained teeth since i was kid, i am now 27?

i just recently got my braces off after 2 years so i wanna work on getting them back to white, i would need to have bleaching from a dentist which is expensive as they recommended to me the ones in the store will not work on my teeth at all. i recently switched from a manual toothbrush to a colgate motion electric toothbrush, is it possible it will remove hard tough stains within time? as i have noticed white spot marks on my teeth, is it removing the plaque???or is something else happening???