Your forks are probably binding (not aligned correctly.) Put your bike up on a stand (front wheel off the ground.) Loosen the axle pinch bolts. Spin your wheel and grab the front brake to stop it a couple of times. Tighten one side and spin the wheel again. Tighten the other side. Also make sure that your forks are even with eachother in the top of the clamps and your clamp pinch bolts are not too tight.
I had new seals put in my KX once with the same experience. They felt super stiff and harsh, just like you are describing. The forks were binding, I fixed that and they worked like a charm. :thumb: