Squealing and grinding. NEED HELP!

There is this incessant squealing and grinding coming from my brakes. I have taken my 2010 Hyundai Accent to FOUR different mechanics and none of them have been able to figure out what is wrong with my brakes. I have replaced all of them and each mechanic has cleaned and adjusted them. But THREE days after, every time without fail, it is back as bad as it was before. It is only the rear right brake drum that is doing it still and I have no clue what to do. I am not a car guy and I have minimal knowledge with cars but something is definitely wrong with this car. Please help!

I don’t think its your brake although it might help if you described the conditions when the squeal occurs and what makes it change.

Does it squeal all the time or only when the brakes are applied?

If all the time, does it change pitch or volume when you go around a right corner (lower) or left turn (louder)?

Does the pitch or volume change with speed?

might that be the parking brake in question then?

Try factory shoes on the rear.