After all long distance trips in my 2009 RX 8 when I finally stop and try to take off again, (like coming off interstate), my car seems to drag in the rear, makes a weird noise like im going over a washboard....can someone help me figure out what it is?

 

may need more explanation on the noise but sounds like its a rear caliper that is sticking on. if a caliper is holding pressure, alot of times it will be fine when cold but as you drive the heat created will cause the held pressure to expand to more pressure. This causes your brakes to drag on that caliper. as far as the noise your explaining though it sounds more like a wheel bearing, the noise is very common but you will rarely feel rolling resistance from a bad wheel bearing even if it is severely worn.
Jack it up after you get home from a decent drive and see what wheel is hard to turn.