Hi, I m a 18-year-old male. For the past couple days I ve been experiencing a weird, pop-like feeling directly under my left rib cage. It s almost like a baby s kick, Which is obviously not possible. There s no pain in that area, But up my ribs there s sharp pains that come a little after the pulsating starts, With A tight, Cramping feeling in the back muscles opposite to the pulsating area. It first came up after a walk across town, I ve been known to have palpitations a lot, Which were labeled anxiety. Could this just be muscle spasms and palps? Cardiologist said I was clear, But A second opinion told me to get a tilt-test, Stress test and a halter-monitor for 24 hrs since It happens when I m more active. Both my grandparents on my father s side had triple bypasses, That s about the extent of my family medical history.