How do pain killers work?

[baiton20]

Can someone tell me how pain killers find the exact source of the pain, and generally suppress it.

[incitatus]

they dont zoom in on an injury, thats just advert blurb. Common painkillers fall into two categories, opiates and cox inhibitors. Opiates work by mimicing the bodies own pain deadening system, the endorphins. This interferes with the chemical transmission of pain in the nerves. Cox inhibitors work by interfering with the enzymes cyclooxygenase 1 and 2. These are part of the inflammation/pain response to injury. The cx inhibitors (aspirin, paracetamol, ibuprofen etc.) turn these enzymes off throughout the body, which is why they can have nasty side effects (reyes syndrome, asthma, rash etc.)