Yes, sibling rivalry is present in other families and, yes, working together in a family business is not easy. You are not alone in your struggles. Even 'good' families have problems. Family members who truly love and care for each other do experience problems. Just because your family has relational problems doesn't mean you are a 'bad' family, or that you've failed as a parent, child or sibling.
Conflict is normal.
Learning to manage and resolve conflict is the real issue. Family businesses need entrance and exit policies that allow family members the freedom either to be a part of the business or not to be. Leaving the business, or not actively participating in it, shouldn't mean leaving the family. Be careful about saying you are running the business for your family. Often our actions communicate something else, that the business is more important than our family.