did someone pour glue onto your brake shoes?
seriously, unless you are the worlds biggest lead foot then your situation is highly abnormal. check the rotor for burs (possibly from hitting rocks) that could be gouging into the brake pads. also put the bike on a stand and spin the rear wheel and look to see if the rotor is wobbly. if neither of these scenarios is the case then just replace the brake pads.
Bleed out the factory installed break fluid and install a good quality DOT4 fluid. If youâ€™re still not happy install a good quality set a break pads. To make the job simpler youâ€™ll want to draw new fluid into the system by using a Might-Vac or a syringe on the caliper rather than pumping new fluid in the tradition way.
New bike? Youâ€™ll want to have a look at the new bike prep section on the JustKDX home page. Make sure you grease those linkage bearings!
Let's bust big . . . I don't think so. Let's bust bark! Now your talking!