Regarding the hypersensitivity of the sole of your foot...have you had any tests done, like an MRI or neurosensory test? Is the hypersensitivity that of a nerve sensations like burning or itching or like electric shocks? Have you tried the Lidoderm Patch? I think that if you haven't had tests done on your foot, then you should.
I know how frustrating it is when you don't know what is wrong with your foot or what treatment will help it the most. I've been searching for months for the proper padding for my left foot that will help alleviate the pain, but some inserts make my foot feel more painful.
At home, I wear cushiony slippers, too. I have hardwood floors and there's no way I can walk barefoot. Out of the house, I wear sneakers now, but they are not comfortable for my problem foot. Wish I could wear comfy slippers out of the house!
I just want to give a warning about having cortisone injections. Those injections come with side effects, some of them permanent. Just be sure to weigh the benefits of cortisone versus the possible side effects. Not all people experience probems with cortisone, however, I had 2 injections and they led to my fat pad on the ball of my foot thinning out drastically. Now my foot is in more trouble than it was before the cortisone shots.