An injured dog can tense the muscles around the injury site causing pain on top of the pain from the original injury.  Muscle pain can develop from compensatory movement patterns. For example a dog with knee problems may hold their leg up off the ground causing tightness in the thigh muscles.  They also may carry their weight more in the front legs to compensate. This can cause muscle tension and soreness in the front quarters and the neck.  Remedial massage can make a big difference to the discomfort that these overused muscles can create.  This relates to a quicker recovery and a more comfortable dog.