Is this heartburn! I've never had this before?

I'm not necessarily nauseous, but i have more of a strange feeling in between my bbs, like right up my esophagus. and every now and then (tmi warning) it comes up like right before my throat. I don't think i'm going to throw anything up but it kindof burns in my upper chest. I might be pregnant and i was just wondering if this is heart burn i've never had it before. Does this sound like the heartburn you had when you were pregnant and also I have a lot of pregnancy symptoms but not nausea, and everyone says you get nausea, is that a bad sign i'm not pregnant? If i am i'm about 4 weeks is that right around when you started feeling heartburn?