Question on solar plexus chakra

[WalkerInTheWoods]

In the area between the third and fourth chakras is an energy storage center.

[IshamaeI]

Hello all,
Just had a question/concern about the solar plexus chakra, the point where your rib cage meets.  For me it seems the most active chakra, which I find a little unusual as it isn't even one of the major seven, located between the third and forth.  Anyways, when I've raised energy up to it, it starts pulsating quite noticably, not just energetically(like with the other chakras), but physically I can watch it move in and out.  I'm kinda skinny so that might be why it moves so much (it creeps one of my friends out...), but I was wondering if this was normal and/or if anyone else has any similar experience.
Any input would be appreciated,
Nate