ABS light comes on

I don't know what the ABS would have to do with the truck being hard to strt, but the shop may have dinged a ruluctor, or wheel sensor during the brake job, have them re-inspect thier work and fix what they did wrong. First step is to read the codes with a scanner that can read "C" codes. This will point you to the affected are of the ABS system. As for the starting problem, check the vacuum hoses near the master cylider, see if the shop maybe knocked one off.