I was wondering the same thing Tisha was...what happened to start all the screaming and it being continual? I never spanked my child. If she had a meltdown in a store, we'd leave immediately. Change the environment. It only happened if she was over-tired.
I never gave in on buying toys and candy "on demand" so that was never an issue. My boyfriend spoiled his daughter too much as a toddler. She'd have a tantrum in the grocery checkout line if she didn't get candy. He would always give in. I just stayed out of that and didn't go on those grocery trips often.
Probably got off-topic, sorry.
Is the screaming child a family member? Forcing food? Hitting, too? It sounds concerning and violent.

Admittedly, I'm sensitive as to violence. I do not like it at all and I'm gentle. I definitely got frustrated as a parent but never hitting, ever. Maybe it's cultural. I hope things are ok.