Back spasms are a sudden and spontaneous contraction of a muscle that can be very painful. There are a number of different causes of spasms.

Individuals that have been through other back injuries or pain can experience back spasms. Often they result from a back or muscle injury. They can also be caused by nerve irritation or even sciatic nerve pain. When they result from nerve pain they are especially painful.

Individuals that have not been through accident or back pain can still experience back spasms. It does not require severe circumstances to get spasms. Sometimes a back spasm can come on just from sitting to long or sitting with bad posture. Also if one has a weak back they can occur. It is more likely to happen in obese people because they often do not have good core strength. Sudden movement such as bending and twisting can also trigger a spasm.