With trigger points, which can crop up anywhere in the back, the message gets garbled. It all starts with a strained muscle, maybe too quick a look over your shoulder, a golf or tennis swing. The strained muscle is painful, it irritated a nerve and off the message goes to the spinal cord. “Contract! Get outta there!” comes the command. Only this time, the muscle can’t move so it contracts in place and if it happens to be wrapped around a nerve and irritates it, the same message goes around again. And again. “Contract!” “Ow!” “Contract!” “Ow!” Symptoms can be painful and even lead to numbness or pain down the arms or legs (sciatica if the trigger points are in the low back).