Hi Rhonda......it probably is just heartburn
, however, if the pain is severe and you're feeling nauseated, you should go to the ER. It could be an ulcer. A couple months ago I thought I was just having severe heartburn, but it turned out to be 2 duodenal ulcers and it was a good thing I went to the er because they admitted me for 5 days. Better to be safe than sorry.
Of course, it could be a heart attack as well, but you're pretty young for that.