Sprains and strains are two types of soft tissue injury or damage. A sprain is a joint injury that involves tearing of the ligaments and joint capsule. A strain is an injury to muscle or tendons.
A sprain occurs when one or more of your ligaments have been stretched, twisted or torn, usually as a result of excessive force being applied to a joint. Common locations for sprains include the knees, ankles, wrists and thumbs.

Symptoms of a sprain can include:
Pain around the affected joint
Being unable to use the joint normally or being unable to put weight on it
Swelling
Bruising
Tenderness

A strain occurs when muscle fibres stretch or tear. They usually occur when the muscle has been stretched beyond its limits or it has been forced to contract (shorten) too quickly.

Symptoms of a muscle strain can include:
Pain in the affected muscle
Swelling
Bruising
Muscle spasms (when the muscles contract tightly and painfully)
Loss of some, or all, of the function in the affected muscle
Blood collecting under the skin at the site of the strain - this is known as a haematoma, and it may look like a large, dark-red bruise

Treatment for sprains and strains -
Treatment may include:
Exercises, under the guidance of your doctor or other health professional, to promote healing, strength and flexibility.
Manual techniques, such as mobilisation and massage.
Electrotherapy.
Pain-relieving medication (talk to your doctor or pharmacist before taking any medications, as they can sometimes disrupt the healing of soft tissue injuries).