Trigger points are usually caused by...
A trigger point is formed when a muscle is stressed or injured. They are hyper-irritable spots which can cause significant pain. If you apply pressure to a specific spot in a muscle and felt a knot form, this is likely to be a trigger point. They can vary in size and can be described as a series of small lumps, large lumps or rope like.
Trigger points can refer pain to other muscles - so one trigger point can create pain in a nearby muscle. An example of this is - many people complain of tension in their upper shoulders and neck when they are stressed. The upper trapezius trigger points can refer pain to the base of the skull, around the ear and to the temple. If you are feeling an ache at the back of your eye - it could have originated in a muscle at the top of your shoulder!
There are two phases of trigger points - active and latent. Active TP is painful when pressed and can cause pain to the surrounding muscles. It causes a dull burning pain or a numbness and fatigued feeling. Latent trigger points can develop anywhere in the body and will lie quietly within the muscle. They shouldn't be too painful and do not cause any pain in other muscles. However, they may cause restrictive movement, stiffness and distorted muscle movement patterns.
Trigger point therapy includes applying direct pressure to the area, reducing pain and tension. It aims to alter the chemical reaction and cause the muscle to spasm.