I am having painful chest tightness, especially when i breathe or drink water. I also checked my heart rate, and it was 115 in one minute. My heart also keeps switching from beating heavily to beating normally. This pain has been occurring for about 30 minutes. what should i do? I don't think it is a heart attack because I am only 16 and not overweight. I also don't think I am anxious, besides being worried about my chest.