My Heart Is Beating Very Strongly.Is It A Symptom Of Panic?

My heart feels weird today. it feels like its beating really strong and tightness in chest maybe muscles? this started yesterday. it s nothing big or a huge problem. but it feels like my heart is beating strong like in strong bangs i can feel it in my chest. Not fast but it feels like its really pumping away hard when i m just sitting on my chair. and theirs like some sort of tightness where my heart is i think it might be just my muscles but its bothering me. it s been happening since yesterday. i m not sure if this is normal or not but it s freaking me out. i m only 15 i have atrial ferbilation(sometimes) what usually happends when i get atrial ferbilation isnt happening now it feels different my heart isnt going fast it just is beating strongly and my chest area around myheart is hurting a bit and feels like theres pressure around there. what s happening is this seriose? or should i just ignore it. or is that like a symptom of panic? because the past few days i ve had panic and anxiety a lot. ? atrial fibrillation****** no this heart feeling like tightness is the first time i ve ever felt it.