Last couple weeks I've had chest pain after intense cardio

I'm 27, white, 6'2 190 pounds with usually a resting 50 bpm heart beat. I've had anxiety attacks the last couple years that I thought were heart attacks but the doctors that looked at me and EKG'd me said my heart was fine and it was due to anxiety.

I'm not sure if the chest pain is related to my heart, it is usually located on the right or left side of my chest and feels like it might be muscle related (the workout has lots of pushups at rapid pace). The pain sometimes get worse of I twist my torso but if I press down on my ribs I don't notice it.