08 1k rear brake caliper grinding
So last night I finally got my bike rebuilt after it was stolen and wrecked. Bought and installed a new M/C and rear brake with new pads as well. Put brake fluid in and properly bled until no air remained in line. now I'm having an issue with the brake pads slightly grinding up against the rotor. I checked to make sure the axle is aligned properly on both sides and it is. I noticed that the piston inside the rear brake is not decompressing when the brakes aren't being applied. Surely that could be the issue...? Right? Rear brake caliper is new though so im not sure why that would be happening. I'm supposed to head out of town this evening and could use any advice on what to look for or check next.