Pain is classified into short term acute, long term chronic. You've got nociceptive pain, which is simply stimulating the nociceptor and you can do that through inflammation or mechanical, thermal, or chemical causes. You have neuropathic pain, which was damaged or a lesion directly to the neuron itself or of the neuron. That's sometimes called nerve pain. You've also got referred in phantom pain - where we actually don't know what the original cause is. It could be brought on by just non-painfully activating that neuron.