The meaning of phantom according to English dictionary is related to paranormal, ghosts and mental illusion.
Phantom pain is a very bizarre phenomenon of mind in which we feel pain in the body organ that we don’t have or the pain in phantom limb!
Phantom pain is a subject of neuroscience and philosophy of consciousness.
Phantom limb is a sensation of a person in which he fells that his amputated limb is still attached with his body.
How our mind works exactly is one of the biggest mysteries in modern scientific community. Even though we humans have made so many artificial minds or Computers using our fullest effort not even the most perfect among them is not even near to the complexity and power of mind of a cockroach. This proves how much complexly our mind works.
Here is a simple visual illusion experiment to know how our mind works.