Scary pain

I'm not sure which issue it's from but tonight Emily scared me for a few minutes.  It's hard to get an accurate description of pain from an 8 yr old that's always in pain.  She told me tonight that she had a "beepy pain" in her chest, on her left side.  The pain was right over her heart.  Thank you, God... it only lasted a minute before moving to her leg, and then back to her chest but in a different area.  I'm not good at counting beats but her heart didn't seem to be at an unhealthy pace.  It just scared me.  I have no clue what that would be from.  She's not systemic JRA, so probably not from that.  She's linear (skin involved) scleroderma.  I don't think Raynaud's would do that.  Her doctor mentioned Mixed Connective Tissue Disorder (MCTD).  I haven't had a chance to read anything new specifically on that yet, but I know that all of the other issues are related to MCTD's.  I've been slacking on my researching this week just because I feel a bit overwhelmed as it is.  I'll pick it back up in a few days, but at the moment I'm still recovering from that last doctor's appointment.  I just wanted to share that with you because it's fairly rare that I get scared in such a way.  Input?  Ideas?  Suggestions?  Please feel free!!!