My chest hurts. i think it's heartburn. i'm 11 weeks pregnant. is it heartburn?

Maybe, but...: Heartburn is very common in early pregnancy (some hormones relax the lower esophageal sphincter &/or alter GI transit), & everyone is now aware from the news of hyperemesis in the first trimester. Chest pain, while possibly of esophageal origin, however is a different matter. If there is any doubt, especially if symptoms persist after antacids, see your doctor & get appropriate treatment.

Probably: It is very unlikely that a 30 yr old woman would be having angina. Gastric reflux can be fairly common with pregnancy. However, you should mention it to your OB just to be safe.