Hi Agent B,
I think you just told us what was going on!
You were there, you had the experience, it was, what it was(literally). Your meditation practice is progressing, you feel improvement, this all feels good, and natural. This energy sensation came, within this positive growth. I am thinking,,,you didn't mind this sensation, and it 'seemed' to you, perhaps, like a good thing...If so, that tells you something, and you can trust that. 'Best' thing to do, is simply continue your practice. Thank you for doing the work you are doing.
love,
gallen