I also have a bedroom that gets hot during the day.
I put a fan on the roof to pull out the hot air in the attic and put extra insulation over that room. It helped some, but it's still hot and my SIL who is in construction said to put up more insulation on the wall where the sun hits. He said I would lose about 4 inches of the room, but it would stop most of the heat. If you touch your walls, are they hot or cold? I also put a tree in the yard to shade that side of the house, but it's not big enough yet to do the job.
Syl