I've so been there and probably worse. I was the parent that everyone looked at like "what is wrong with that child?!?" (But I knew what was wrong with her and it was no one eles's business...so I am the first to say that no one should judge what they see at face value because they may have no clue.) That said...a few things saved my sanity.... first and foremost...research your area to see if they have "playcare." which is hourly drop-in-daycare. Here in Dallas, we have AdventureKids, and I am the first person to say that AdventureKids changed my life, literally! I flat out quit taking my daughter to do most errands with me at about 2 1/2 -3 1/2...it is so much easier to do that stuff alone And, I didn't have to schedule sitters that way.
A few other tips that I picked up from the play therapist... give your child a ton of nurturing. He's trying to get to you in the kitchen because he wants to be with you. He's at a significant attachment age (research "attachment parenting" for some hints on that), and he's wanting that connection to you. Can you sit with him a few undivided minutes (even set a timer) before going to the kitchen so that he has that need met and can give you some space? It will give him security which will help calm him.
Either quit going to sit down restaurants with the kids or go to ones that immediately start bringing food (Olive Garden, Cheesecake Factory, Mexican, etc) to keep then interested. When the kids get fussy, take them out of the restaurant. I always go somewhere where it's going to go fast with continual food (and let her bring in a quiet toy) and pull out my credit card as soon as the food is served to have the check paid so that I can leave as soon as I sense the "well behaved" window is closing.
Leave when behavior is inappropriate. I've carried a screaming, flailing child out of everyplace from retail stores to McDonald's to the swimming pool, GIve them a warning that if they do not stop a behavior or do a behavior that you are gong to have to leave, and then do so. Now, I've often only carried her as far as the car where I put her in and let her have a screaming fit while I stood outside the car casually reading emails or sat inside the car totally ignoring the tantrum by doing something else. Once the tantrum subsides, do not return to the activity...just assure your child that you still love them and drive away. from the activity. n
Finally, children draw calmness and security from adults' strength. As frustrating as all of this is, you have to remain as calm and non-emotional in your speech and actions as possible. The more upset you get, the more insecure they feel and the more it will spiral downward. It's amazing how much that helps in keeping them calm. And, if they are driving you crazy, it works best to talk less to them because sometimes our talking is just our own manifestation of our anxieties. If you are at the end of your rope, tell them "I am not going to be around this behavior right now" and take yourself to your own room and lie down for a few minutes for your own time out. Of course, regimented routine works wonders and making their world really small with limited outside stimulation (stores, restaurants, etc) when they are having behavioral issues can also work wonders.
Good luck! I have so been there, and even tonight had to come home vs. taking the daughter shopping because she was backtalking and misbehaving.
P.S. - the other thing that helped some was doing "silly time" with her every day, One day I realized that I probably wasn't all that much fun to be around because I was so stressed about all that wasn't going right. So, I started taking some time to do an impomptu dance party,holding my nose and talking or making fish lips and silly faces at each other. It's fun and has an element of surprise...amazing how much you'll both giggle.