Myofascial pain referral is still a somewhat controversial topic.  This is surprising, as it is common (and very old) medical knowledge that pain can be referred.  For instance, in a heart attack, pain/tingling is often referred to the left arm or chin. In a similar fashion, muscles/fascia can refer pain to more distant structures, often down the limbs. 

The site of greatest muscle spasm (and the source of the referral) is called the "trigger point".  I often find this variet of pain referral after whiplash injuries and the concerned patient comes to me very concerned about an unremitting spasm that radiates tingling or burning pain down the arm or leg on the involved side.  They are concerned that a "nerve is being pinched".  Happily, a deceptively simple treatment with just a myofascial trigger-point saline injection or just needing alone can greatly aid in the recovery, and almost always eliminates the burning and tingling feeling down the limb.  The following image(s) show some examples of myofascial pain referral patterns.