Am I doing the right thing?

My son is 4 years and 8 months old. He’s always done this thing where we ask him if he wants something, he says no, then 3 seconds later he wants it. We will give him multiple chances to do something (help fill his water bottle, grab a toy for the car ride, set the timer for certain activities) and each time he says no. After multiple “no” answers we do it or he doesn’t get the toy, cookie for dessert, etc. Usually he cries immediately after that’s done and will continue to throw a fit until we give in and dump the water out so he can redo it, give him the cookie, go back inside and get the toy, and so on. Lately we have been trying to NOT give in. I don’t know if it’s working. Tonight I asked him multiple times if he wanted to comb his hair or if he wanted me to do it. He wanted me to. I did it, got him tucked into bed, and then he started crying about how he wanted to comb his hair. I said no. I asked him for a hug/kiss like I do before bed every night and he said no. I said okay and left the room. Now he’s pounding on his door and walls wanting a hug and kiss. What do I do? I feel like I need to stay firm on the decision to not give him multiple chances but I don’t want to withhold affection when he asks.