Hello, I am healthy athletic 15 year old boy that is anxious. About 2 weeks ago, after a three hour intense soccer practice, I started having this sharp pain on the left side of my chest only when I would take a deep breath. I tried sleeping it off but it didn't go away. (I practice 3 times a week regularly) I went to the doctor and they said it could've been a muscle problem and they said to take Advil. The pain didn't go away so I went back and they said it was the same thing because my lungs and heart sounded fine. After a couple of days the pain would eventually go away but I was still worried that something was wrong with my heart because I did a bunch of reading on the Internet that ended up scaring me. A week ago I went on vacation to the beach. I went on a thrill ride which was a boat ride and the lady that hosted it said, "if you have any heart conditions please sit in the back" - that got me scared because I was sort of in the front. So when we were going fast I started to hyperventilate and my legs and arm became numb. I was so scared I went to the ER and they said I most likely hyperventilated because both my legs and arms were numb. I told them about my chest pain so they took an EKG. My results were abnormal, (I was anxious during it so it could have affected the test) and they told me it was very close to normal so to not worry about anything. Now I'm at home and 2 days ago I got what is called a palpitation. I freaked out but started reading and it said it could be perfectly normal. The next night I got another one but it was shorter. (Mind that both of them only lasted about 4 seconds.) I told my parents and they scheduled an appointment for Thursday with a cardiologist. Now it's 2 days after and I feel perfectly fine but I still want to go because what if I have something underlying that I don't know about. I have mucus in my throat and after a soccer practice on Sunday I felt like fainting (lot of running) I only cough when I feel mucus in my throat. Also know that when I was a infant doctors said I had an enlarged heart but I grew into it when I was 3, maybe this can affect me but I'm not sure. I always read online and scare myself because most of my symptoms are for critical medical condition. Then my dad told me I wasn't drinking enough water, and all the symptoms do correspond to dehydration too. So I started drinking more water the last few days and I feel better. I'm writing this to hear other opinions from people that have had the same thing. (The chest pain comes sometimes but doesn't really hurt)