The kitchen and downstairs outlets are connected to this breaker as well...

Something is wired wrong, or a hot wire came loose and is touching metal.

Lighting and other rooms are not allowed to be on with kitchen receptacles also.

Stan,

Question, I thought that restriction only applied to the receptacles that serve counter tops in a kitchen. Am I incorrect?

Unless a receptacle is in a place where it can only serve lighting, such as for above/inside cabinet lights, etc, a receptacle in a kitchen is still considered part of a SABC.