I was sleeved on June 4, lately I have been experiencing a burning sensation throughout the day, even when I haven't even eaten anything. i sometimes have a small cup of coffee, could that be the issue?

Make sure you are taking a daily dose of omeprazole, no exceptions! Heartburn is gonna be a way of life, welcome to the other side.

Coffee is acidic so it could be contributing to the problem. Go a couple days w/o it and see.

Does any heartburn medicine work better than others? I tried target brand and did not feel any better. Do I really need to take it every morning for the rest of my life?

I have the same issue. I take double prescription strength omemprezole daily. When the burning happens I'll take tums or ranitidine. Sometimes it works and sometimes it doesnt. When it doesn't my pcp gives me carafate

I'm with @Elode....they tell you not to drink coffee if you're prone to reflux. That may be it.