the difference between acute pain and chronic pain

Source: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Acute means occurring over a short time, that is, it refers to intense, short-term symptoms or illnesses that either resolve or evolve into long-lasting, chronic disease manifestations.
Acute pain generally lasts from a few days to a few weeks. To be classified as acute, pain should last no longer than 6 weeks.
Acute pain may be caused by a sports injury, work around the house or in the garden, lifting a load that is too heavy, a sudden jolt in a minor car accident, etc...
Treatment for acute pain involves bed rest for 1 to 2 days, the use of cold and hot compresses, stretching exercises, and/or taking over-the-counter pain relievers to reduce discomfort and anti-inflammatory drugs to reduce inflammation.

Chronic means occurring over a long time, that is, it refers to suffering from a disease or ailment of long duration or frequent recurrence. Chronic pain is pain that persists for more than 3 months.
Common chronic pain complaints include headache, low back pain, cancer pain, arthritis pain, neurogenic pain, joint dysfunction, fibromyalgia, etc...
Effective pain relief may involve a combination of prescription drugs and over-the-counter remedies and may also involve the use of chiropractic, acupuncture, physical therapy, massage therapy, local electrical stimulation, or surgery. Many chronic pain conditions affect older adults.

Another difference between acute pain and chronic pain is that chronic pain requires the assistance of a health care provider while acute pain usually does not require the assistance of a health care provider.