Is it possible to feel pain in some part of a body, but that the cause of the pain is situated elsewhere in the body? For example, somebody feels pain in his toe, but it turns out that this pain is not signaled by nerves in his toe, but caused by a damaged nerve in the spinal cord, or somewhere in the brain.
Yes, this is pretty common. Examples include
- sciatica, pain felt down the back of a leg to the foot, from irritation to components of the sciatic nerve but commonly at the level of the sciatic nerve roots
- angina pectoris, pain from myocardial ischaemia felt in the throat (Latin angina "infection of the throat"), arms, chest etc
- shoulder tip pain from a subphrenic abscess
The clearest possible example of this is phantom limb pain, where pain is perceived to be arising from an amputated limb indicating that the pain is arising from central mechanisms.
An example of pain evoked by distant sites in the body is referred pain. It's defined as pain perceived at a location other than the site of the painful stimulus. An example is the case of angina pectoris (chest pain), caused by myocardial ischemia (decreased oxygen supply to the heart due to a narrowing or complete blockage of the coronary arteries). Angina often results in pain felt in the neck, shoulders, and back rather than in the thorax (chest), which is the actual the site of the injury.
A massage-related field of therapy has evolved around this - trigger point therapy, where trigger points are defined as the cause of pain elsewhere in the body. From personal experience I can add my gratitude to this field of therapy; it's been good to me.
Trigger points. source: Trigger Point Therapy
Another common medical condition that causes pain elsewhere is the spinal disc herniation. The disc pushes against the nerves in the spinal and causes pain, usually in the leg, foot or arm. https://en.m.wikipedia.org/wiki/Spinal_disc_herniation Sometimes the pain disappears with rest, sometimes surgery is necessary and sometimes the pain partly remains even after surgery.
Just as an FYI, the answer is emphatically yes. I have two separate areas of my body which exhibit those symptoms. But my answer does not "track" those of others here. They talk about (I would guess) some relatively standard off-site pain actions. In my case, it appears to be more simply the action of (for want of a better term) CrossedNerves. As one example, there is an area of about two square inches, just right of center, on my chest which, when poked with a sharp object, will cause a stabbing pain to appear on the back of my right shoulder just below the shoulder blade. This is repeatable and has been that way since as long as I can remember. Glad to see I'm not the only one with these strange biological oddities.