2002 GMC Sierra brakes

When you first start the truck the breaks are good but as you drive along and use the breaks the pedal gets hard to the point that you can't push it down. I still have brakes but by the time you drive 20 to 30 Km's they are stuck on. Sometimes it is just one brake that sticks but others it is both front ones and some times even all four. After you leave the tuck sit for awhile the pressure will ease off and the brakes are back to the way they should be until you start driving again. I replaced all brake lines last year and in the process I stripped on of the ports in the abs module so I replaced that with a used one after that I replaced the front 2 calipers. After that it seemed to be good' however I just changed the front rotors and pads and now I have this problem. I also believe I have a bad wheel bearing in the front, don't know if this could have anything to do with it.
Thank you!