Chronic pain is defined differently by different people. For the most part, everyone agrees that pain lasting past the expected time for physical healing is called chronic. Most soft tissue and bone injuries recover in six to eight weeks' time. Factors like poor health, diabetes, and tobacco use can delay normal healing.

According to most research, pain that persists beyond the expected time becomes 'chronic' after three to six months. The doctor's exam must identify whether this is a new (acute) injury or a recurrence of the old injury.

Subacute chronic pain suggests a new episode of back pain that is in the healing phase. Acute means it has recently happened (first one to two weeks). Subacute refers to the period of time from two to six weeks of the recovery process.