Magic Forums

Sometimes when I focus I get a weird feeling as if their is pure energy going trough my body, and it feels nice and warm, but what exactly is it 'cuz it's not something I do on purpose, I just focus on a certain subject or certain things not on the energy.
But sometimes when I was feeling that energy, I get the feeling that it is stuck, most of the times it is somewhere betweet my shoulders so I start rolling my shoulders and sometimes I feel the energy go to my body again until the feelings completely gone, but if that doesn't help I have to really concentrate.
So what is this feeling, where does it come from and why does the energyflow get stuck?
grtz