Muscle
spasm pain can be quite severe. Pressure and Pain receptors in the muscle fibers
become activated and a local inflammatory response is mounted. The increase
in local inflammation serves to increase the pain and further irritate the muscle
in spasm. This does not have to affect the whole muscle and can involve only
some fibers, causing myofascial trigger points. These are places in a muscle
that go into spasm and inflame the covering of the muscle locally. These can
be exquisitely painful and send referred pain to other parts of the body.