It's very possible. In EMS I meet folks that have been in having a heart attack for quite some time, it's not always dropping down like a rag doll you see on TV (though many times it is).

My dad did the same thing, one day he had some chest pain that he thought was related to something he ate. Drove a semi truck around for about 6 hours, decided to come home early. He came back to the shop, parked his truck and called my mom and said he had indigestion like he'd never experienced, and they went to the doctor. Turned out to be a full-on heart attack he'd been feeling the last 8 hours.

I guess that's a long way of saying listen to your body. Generally, it's trying to tell you something, and if feels just a little off, get checked out. Could definitely save your life.