Panic Attack Diagnosed at ER

Male 30yr old 175 pounds. Just got diagnosed with panic attack/atypical chest pain and now I’m wondering how common is my symptoms for a panic attack? Makes no sense to me.I was lying down watching tv and I felt this sharp pain in my center left chest area and throat area.I sat up thinking it was some type of fluid stuck in my throat and my heart started pounding like crazy. I got out of bed stood up and started taking deep breaths to see if my heart would stop racing but I just felt weak in my legs and confused. Symptoms lasted for about 20 min til I got to the er(managed to drive myself there since I only live down the street from it) they ran a ekg and took blood test everything came back normal and dr diagnosed me with a panic attack which I’m confused by because I wasn’t panicking about anything til I started feeling my heart beating like crazy. Is this common? Has anyone else had a similar situation?