brakes binding, and they're either on or off

Been having a few brake issues recently.

firstly, abs error, found broken wire to abs speed sensore... now fixed all been good.

Front brakes were binding so threw it into the guy that does my car stuff for me, he greased up back of pads and possibly slider bolts but not sure... now they are still sticking, not all the time but most of the time, i can feel the resistance bringing me to a stop when coasting up to traffic lights etc. Any ideas?

Also my brakes seem very sharp sometimes, i could put my foot lightly on brake slowing down then off and back on almost straight away they nearly put me through the windscreen (exageration), doesnt seem right to me, anyone experienced this?

cheers