Hi T.,
I have 5 year old son and an almost 3 year old daughter.
This is normal. My son went through this stage as well. My though is that he is looking for your support, and wants to know that you will be there when he needs it. Take care of the needs that he is asking for, so that he will ask less in the future. Doing this will show him that you are there for him when he needs it, so he will eventually ask less sooner rather than later. He will not be doing this when he is 20.
My suggestion is to go with him to the restroom when he asks. If you go with him to the restroom, then he will ask you to go with him less.
Also if you go with him to the restroom when he asks on a consistent basis, for a week or so, then you can start proposing alternatives for him such as, "I will go with you to the restroom, but I would prefer to stand outside of the restroom while until you are finished to give you some privacy," or "I will go with you to the restroom, and then I am going to finish (doing the dishes). I will be back to check on you, or you can call me when you are finished and I will take care of your needs."
My suggestion for him going to sleep is similar to my response to him going to the restroom. Read him a story before he goes to bed, and if he says that he does not want to sleep alone stay with him until he falls asleep, and then crawl into your bed afterward. He may wake-up in the middle of the night, and you will have to put him to bed again as above. After you have waited for him to go to sleep, then go back to bed again.
Your son is only four now. enjoy this extra time to be close with him. He will not be doing this when he is 20. My son is five now, and he sleeps in his bed by himself now. There are times that he requests for my time to go with him to the restroom and to stay with him when he sleeps, but that is every now and again. I find that my son only asks when he really needs me. I trust that you and your son will find your rhythm as well.
I hope you found some of this information helpful, and I wish you and your little man the best.