I'm seeing that the rear brakes on the dsm's are starting to freeze up and drag more and more now. Have those checked out. A good way to know if it is a brake problem...
get up to speed, put the vehicle in neutral and if it seems to still drag that way, Its more likely than not the brakes.
Best thing to do is have them inspected. Hell, bring them to me, Ill be able to figure it out. If not, im sure my buddy out in west fargo will be able to, he needs the business.