I get fluttering in my chest that stops my breathing afew sec. I had an ecko and us 10yrs ago but nothing. I just had a severe attack. What can it be?

Your doctor. Those symptoms can be from anxiety or panic attacks, thyroid function abnormalities, or abnormal heart rhythms that require an event recorder (continuous heart monitoring for several days) for diagnosis. Your doctor can get more information and determine the best course of action.