My name is Alyssa Parker. I am 16 years old and for the past year I have been experiencing a rapid heart rate. However, I have been to a cardiologist who assured me that everything is fine and my heart is completely healthy. Last night I was simply laying in my bed and I realized that there was a strange sensation on my neck..I touched it and could not feel myself touching my neck. Then I realized that it had spread to my chest and it is just on the left side. I also felt very weak. I went to the emergency room and they could not find what is wrong. A doctor mentioned that I might should have an MRI done on my head. Any advice? Please let me know.