Legally, they can kick you out for any reason that isn't illegal discrimination. They can't kick you out for being black. They also can't kick you out for being white. But they can kick you out for not liking your face.
Now the question is: Who can kick you out? The store owner obviously can. Anyone who is given the authority by the store owner can. Actually, anyone with the apparent authority can kick you out. However, everyone other than the store owner has been hired to work towards making profits. If throwing you out is bad for business, then whoever did it would have to answer to the store owner.
So the ex-friend can't go to court for throwing you out, but they might get into trouble with their boss about it.
PS. I interpreted "kicking out" as saying "Please leave our premises. If you don't leave then you will be trespassing and I will call the police", not actually kicking the person with your foot which would be most likely assault.