Hello, and I hope I can help you today. First of all, any woman having unprotected intercourse has a risk of pregnancy. However, heartburn is a common medical symptom that most commonly occurs due to something (food, drink, or medication) that you consumed rather than as a sign of pregnancy. Pregnant women get heartburn, but mostly later in pregnancy when their enlarging belly pushes their stomach higher in their chest. Secondly, the most common sign of pregnancy is missing your period. So if you are menstruating regularly, it is unlikely you are pregnant. The painkiller you took, Naproxen, can cause heartburn as a side-effect. So I suggest you purchase an over-the-counter medication to treat heartburn. Antacids are effective very quickly and can be taken every 3-4 hours. Keeping your stomach a little bit full with bland foods like bread, rice, dairy products and avoiding spicy food and alcohol can also help your symptoms. Modern pregnancy tests are extremely accurate, and will become positive 10 days to 2 weeks after conception. So if enough time has gone by since you have last had unprotected intercourse, I recommend you perform a test, but again, heartburn alone is not really a symptom of pregnancy. I hope I was able to adequately answer your question today and that my advice was helpful. Best wishes, Dr. Brown