You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Myofascial pain syndrome and explain in detail?
Myofascial pain syndrome (MPS), also known as chronic myofascial pain (CMP), is a syndrome characterized by chronic pain in multiple myofascial trigger points ("knots") and fascial (connective tissue) constrictions. It can appear in any body part. Symptoms of a myofascial trigger points include: focal point tenderness, reproduction of pain upon trigger point palpation, hardening of the muscle upon trigger point palpation, pseudo-weakness of the involved muscle, referred pain, and limited range of motion following approximately 5 seconds of sustained trigger point pressure.The cause is believed to be muscle tension or spasms within the affected musculature. Diagnosis is based on the symptoms and possible sleep studies.Treatment may include pain medication, physical therapy, mouth guards, and occasionally benzodiazepine. It is a relatively common cause of temporomandibular pain.

Signs and symptoms
Myofascial pain is pain in muscles or fascia (a type of connective tissue that surrounds muscles).  It can occur in distinct, isolated areas of the body.  Because any muscle or fascia in the body may be affected, this may cause a variety of localized symptoms.Generally speaking, the muscular pain is steady, aching, and deep. Depending on the case and location the intensity can range from mild discomfort to excruciating and "lightning-like". Knots may be visible or felt beneath the skin. The pain does not resolve on its own, even after typical first-aid self-care such as ice, heat, and rest. Myofascial pain syndromes are characterized by localized pain in an area of repetitive use or trauma with resultant trigger points that cause non-dermatomal pain radiation upon palpation.  Autonomic dysfunction and spontaneous EMG activity can be seen in the affected region.

Causes
The causes of MPS are not fully documented or understood. At least one study rules out trigger points: "The theory of myofascial pain syndrome (MPS) caused by trigger points (TrPs) ..