Why wont my injured heel respond to treamtnet and why aren't painkillers working?

Unknown. Often heel pain requires a combination of different treatments. There is not a single 'silver bullet' for heel pain, although some may only need to stretch while others need physical therapy, orhotics, cortisone injections, sonic shockwave treatment and on rare occasion surgery. If pain killers are not helping then making sure that your foot pain is correctly diagnosed is important.
Not enough info. You don't indicate what type of injury, or type of treatment that has occurred.