is the scraming part of a tantrum. I've had this with my son. My neighbors actually complained to the office about it. Which made me feel EVEN more anxious about it and any noise he makes. The screaming is already anxiety producing enough. Have you tried ignoring her when she screams and does that help? Sometimes kids just hae to have a tantrum.
I would get her out more if she is cooperative and do physical activity.
Keep your voice calm and even, keep your personality calm and even. Don't give her anything to get upset about, etc.
Hm. From your brief description is hard to know how to help. Some kids are definitely more high maintenance than others and require much more of our patience.
What is she screaming about? Is she just screaming or screaming at you with words? What proceeds the screaming?
What forms of discipline have you tried? What is she being punished for?
Does she attend preschool? If so, how did that go? Any issues there? What about daycare?
So, I will try to help more if you give some more background.
But, a basic rule of thumb with a tough child is to give them choices. You decide what the choices are so she is still doing what you want----------- but by choosing, she feels a little in control and is more apt to comply. Structure is good for little ones such as this. Keep her busy with games, coloring, etc. Try a reward system. You could have her earn beans for good behavior (listening, helping you)------- and then put them in a jar. When she gets to a certain number, she gets an outing of her choice. It can be very motivating and switches attention to positive attention vs. negative. You can try some special things with just her in case she is jealous of her little sister------ make sure she feels special. I'd also say to pick your battles. Not everything can be a no. Then pick one or two things to work on at a time. Small steps for improvement.
Physical activity is valuable for improving behavior. Get her to a park and let her run it out of herself. good luck