Pain is a complex, subjective phenomenon that involves biological, psychological, cultural, and social factors. To put it succinctly, pain is whatever the patient says it is, and it occurs whenever she says it does.
The only true authority on any given pain is the person experiencing it. Therefore, health care professionals must understand and rely on the patient’s description of her pain when developing a pain management plan.
Below table may help you to understand the drugs that are used to control the Pain..