Hi, I started working out again in January. I have been inactive for about 3 months due to joint pain. Last week, I felt a throbbing in my chest while I was running. It was right in the center of my chest... it wasn t painful but it felt weird... Today, I was working out at home, doing lunges, step ups, squats, and I felt it again. like myheartbeat was stronger?? I ve never felt this before... br