Repetitive transcranial magnetic stimulation and transcranial direct current stimulation are currently the two main methods of non-invasive brain stimulation under investigation. Stimulation of the primary motor cortex has been reported to relieve neuropathic, musculoskeletal, visceral pain as well as headaches and migraine. Other parameters of stimulation have shown encouraging results. For example, stimulation of the secondary somatosensory cortex was also reported to relieve chronic visceral pain. However, there are numerous unanswered questions regarding these techniques.