Why I focus in my heart so much I feel lik it just gone stop why I feel like it i, m so freaking out?

Anxiety maybe? You may have a legitimate heart issue, so get it checked out. But if that is all fine, do you think you might be experiencing anxiety? Anxiety is very very common and nowadays there are some really good treatments for it, both counseling and medications. Don't freak out, solve the problem and see your doc.