The most likely explanation is that this guy has an intervertebral Wikipedia reference-linkfacet joint inflammatory event , which is giving him referred pain to the chest. Spinal joints will become inflamed for long periods at the effect of a protective response , probably initiated by his fall. Mobilising the relevant facet joints will quickly eliminate both the protective response and referred pain associated with nerves irritated by close proximity to those joints. Continuous Mobilisation is the method most likely to bring about resolution , other methods like Maitland and Mulligan have some value also.