D.,
Could you please tell us how old your son is, this way we can provide the best age-appropriate advice? I'll check back shortly...
Okay-- almost five. ugh. First, yeah, you probably do need a day off..or three.:)
But I would go with a two-prong approach. First, simple choices/consequences. Second, positive reinforcement for behaviors you like to see.
And there's always ignoring.:)
Let's start with that. Some of what's going on can be ignored. First, you CAN go upstairs to put laundry away. Before you go, remind him "I'm going upstairs; if you need me, you need to come find me." Then, when he hollers and hollers, ignore him. Believe me, D., your son sounds like mine some days and mine is six. They are just so self-absorbed in what they are doing that they call out from wherever, expecting us to come when called. So, instead of responding like a trained pet, I now ignore anything other than "I'm hurt". They *do* eventually come find us if it's important. I promise... :)
I find that choices and consequences work well so long as we keep reminding them and give them some structure. "The couch is not for jumping. You may sit on the couch or you may sit on the floor." or "You must stay off the couch now, or you will need to spend some time in your room/in time out/(wherever works for you)." When my son is being goofy in how he sits at the table, I take his chair away and have him stand for the rest of the meal. Keep the either/or choices simple.
For your son, at this age, you should be able to get on the phone without a lot of fuss, but you have to be proactive about it. I used to schedule some phone calls (the chatty ones with friends) for a time when Kiddo would be either watching a half-hour program OR put on a short dvd. If I was on the phone at other times, I would tell him "I'm on the phone now; it's your job to let me talk and go play. I'll be off in 15 minutes when the timer goes ding." and I used a timer to reinforce that. Several times when he continued to interrupt, I walked away into another room and closed the door, used my body to block him from coming in. And then ignored him. (He knows that the only reasons for interrupting me or bothering us after bedtime is "if you are bleeding, throwing up or dying"... it's extreme, but when they are independent in the bathroom, there's no reason to be hollering at us for attention when we are otherwise engaged.)
If he starts in on your little one, then he needs to go to his room for ten minutes. I'm super clear that if you can't let me do my work, you go to your room. If they share a room and he's not being safe, then you put him in a boring place near you and make him sit quietly. Do not talk to him while you are doing your work. Just "You must sit here because you are not being safe." and no emotional response from you.
I encourage you to have him 'trade jobs' with you whenever possible. What can he do around the house? When he whines at you when you have just sat down, say "great, I'd be happy to get you a snack in five minutes, after you have (taken recycling to the back door/straightened up the shoes by the door/put your toys away... etc.)" If he whines again, just a one-word answer "recycling" or "shoes" or "toys"... repeat it like a mantra. Stay calm. Or if he's in badgering mode, another option is that when he asks the second time, you say "are you asking me again because you think I'll change my mind?" When I have done this with kids, they nearly always say 'yes', and then I reply "I have already told you my answer. I am all done talking about it and I will be happy to talk with you about something else." At this point, I actively ignore the nagging and will only talk with them when they have changed the subject. I am calm when I do this, as if their whining and nagging is nothing more than a gentle breeze blowing through. When we stop responding with strong negative emotions, they realize it's not going to work to continue on; they get bored and move on. Or they don't, and they we remove them to their room, also calmly. OR we can, once again, remove ourselves. More than once as a nanny and as a parent, when the kids were being disrespectful, I have declared coolly "I'm taking a time out now." and walked into the bathroom and closed the door without fanfare. This usually makes a big impression. For parents, giving them no attention for annoying behaviors is often better than negative attention. If we were at a party and someone was annoying us, we'd move away, right? Same idea.
(And to augment My Missions' suggestion, I used to do 'snack boxes' for the kids I nannied for. It was a larger Gladware container with healthy snacks for them to choose from in the fridge: yogurt & a spoon, almonds, baby carrots, cheese sticks, crackers, half a sandwich... "go get your snack box" was pretty common, esp. in houses with multiple children. You eat what's in the snack box, nothing else.)
The endless questions... I answer the first and the rephrasing, and then I ask "what do you think?" If my son answers "I don't know" then I usually say "well, think about what you just asked..." Some people do not agree with this, but I do think that if they are getting their need for attention pretty well met, (not the desire for constant attention, but the *need*) then it is okay to ignore repeated questions. I mean, this is what their peers are going to do at some point...
Is he in preschool, by the way? I don't know your son, but it is helpful for *us* to have the break and for them to learn how to be with others. Peer correction is a wonderful thing...
Lots of positive praise every time he comes to you to ask a question instead of yelling (Thanks for coming to find me...) , when he doesn't interrupt phone calls (Thank you for being quiet/waiting patiently while I was on the phone,...) when you like what he's doing. And one guaranteed game-changer is to give him lots of nonverbal positive attention during times when he is *not* seeking your attention. This is a rub on the back, a gentle squeeze on the shoulder, tousling his hair when you walk by... physical acknowledgment is a very powerful thing. One woman ( a mentor, older mom and preschool teacher) I admire said we should strive for at least 20 of these interactions a day, when our kids are busy doing something *they* enjoy which is not a bother for us. When my son was exhibiting attention-seeking behaviors (via misbehavior) I would load up a pocket with 20 craft/popsicle sticks and then take one out and put it elsewhere every time I gave him that positive nonverbal attention. It DOES work. They feel noticed at the very best time-- when they aren't seeking our approval or bothering anyone-- this is what Mazlov called "being love" or being loved just for being alive, for being who they are.
Be sure, too, that you begin to enforce a 'quiet time' every day. Use a timer and start small, but he needs to have the break and so do you.
By the way, I know this was very, very long and I do apologize for the length. Just know that you have my empathy and commiseration... and that it *does* get better! If he's anything like my son, he will eventually discover Legos and then you will hardly ever see him unless he needs you to pull the pieces apart.:)