For example, if you were crossing the road Joint Pain Hack Review and trod on a nail you would expect this to hurt (nail into foot, tissue damage, brain receives danger signals from foot via spinal cord and responds with pain to motivate a limp, shout etc). However, if you were to tread on the nail and a bus was careering towards you, the foot would be the least of your worries!
So what is happening? With an acute injury such as an ankle sprain or a wound, the damaged tissue releases various chemicals that sensitise the nerves. These nerves are usually quiet and only respond when excited by certain chemicals; i.e. their threshold for firing signals is lowered. These nerves send 'danger' signals when excited to the spinal cord where they communicate with further nerves called secondary neurons.
The bombardment of signals causes sensitivity to develop within the spinal cord meaning that subsequent signals are amplified. To us that will mean that in this sensitised state a painful stimulus applied to the affected area will be more painful and a non-painful stimulus (light touch, pressure) would be painful. Think of a hot shower with sunburn or pressing a bruise.