What is the treatment of heel pain?

Hi doctor,

Three days ago, I woke up with stabbing pain in the bottom of my right heel. It hurts to walk, and there were no previous injuries or unusual activities that could have caused this pain. I massaged the heel the same day and noticed a small flesh-colored bump on the inside of the right heel (under the skin, not a wart). When I pushed on this area, the pain in the bottom of the heel seemed to release somewhat, but the bump turned red or purple under the skin. Now, I have pain in both the bottom of my heel and the side of the heel where this bump is. I went to a podiatrist today, and the X-ray was normal with no findings. He is unsure about the heel pain and the bump and suggested a magnetic resonance imaging (MRI) if it does not improve in a week. He mentioned that the bump could be a possible small cyst or vein problem. I have read about piezogenic pedal papules and think this bump could be that, and maybe I popped it when I pressed on it. However, I am unsure about the heel pain. I am scared but can not afford a magnetic resonance imaging (MRI). Please help.