Accord2000V6

I have a 2000 Honda Accord sedan about 118,000 miles and running strong. My girlfriend and i were traveling back from Georgia a week ago and kept hearing this loud humming/groaning noise resonating from the back of the car. My first instinct was flat tire but after inspection turns out it wasn't. My though is the bearings either need repacking or replacement. Has anyone else heard this as well or have an idea of what it could be? If it is bearing how much did you pay to have them replaced? Thanks for the help
Brian

JimBlake

Bearing is part of the rear hub, & it's not too difficult to replace. If you've ever replaced your rear brake rotors (or drums) it's not too much more than that.