On my left side my upper right tooth separated and now i have a gap. i know the best thing is for me to go to the dentist but i am scared for bad news? whats the cause of separation of tooth?

Most common cause would be you have lost some teeth close to the one that is moving. Or you could have acromegaly. Google Acromegaly and look at images. Observe teeth to see if match yours. Better yet see you dentist. Many are scarred of dentists and even i would prefer not to go.

Many reasons. Missing tooth in area, pressure from abnormal bite, grinding teeth at night, trauma to area, bone loss and biting on hard object. The bad news is if you don't see a dentist than it will get worse.

Malocclusion, gum disease, fractured tooth, neoplasm. Whatever it is, it's fixable. The longer you wait, the more complex the problem may become. Please stop inventing scary scenarios. Call your Dentist, seek an examination, diagnosis of the cause for your tooth movement, and appropriate treatment.