If you are only 17 I would say it is unlikely that you have heart problems. However, EKGs do not show everything and you should definitely ask about wearing a heart monitor to check it out. The reason why I wouldn't blame anxiety just yet, is because you used the description of squeezing and the fact it occurred when you were lying down. That is a lot different from anxiety chest tightness. Do you cough or anything? Asthma can cause a feeling of that nature and you don't have to wheeze to have asthma. So it could be anxiety, but I would definitely look into it more before assuming that