Interestingly treatments which cause activation of pain fibres can actually improve pain in some situations. Capsaicin (the spice compound in chillies) can be used as a topical treatment. It causes temporary activation of pain fibres followed by a more prolonged desensitisation which improves pain symptoms in neuropathic conditions such as post-herpetic neuralgia.

Capsaicin has actual physiological effects on pain receptors, but there is also what is called “gate control theory” which is the principle that when your pain receptors are activated, addition of a non-painful stimulus can overwhelm a painful stimulus and reduce pain- it’s why when you bang your knee you rub it and the pain reduces.