If the OP's bike came with an Avatar, that ain't flat like a Fizik Arione is flat. It has a bit of curvature/hammock effect to it.
My therapist hooks me up to some sort of electrical device that makes my lower back and butt tingle. It actually seems to help.
That's e-stim, or electrical stimulation. It helps relax muscles by over stimulating them in a variety of patterns (controlled by the machine and set by the therapist), also helps with blood flow. If I could have one of those at home for teh cheap, I would.