In the past, it wasn't unusual for a doctor to tell a patient to remain at bed rest for weeks, even months. Research now shows prolonged bed rest does more harm than good. Studies on acute back pain show two days of bed rest is as good as a week or more in terms of allowing the strained muscles to unbind and relax. When bed rest and ibuprofen or aspirin don't help within a day or so, you should seek out a back specialist, because this is often a sign that something more serious is wrong. Ice and heat can alleviate local pain that comes from muscle and ligament strain.
Heat increases blood flow to the deep tissues, whereas ice acts as a local anesthetic.
Research shows that ice slows the swelling and inflammation that occurs after injury. It also acts as an anesthetic by numbing sore tissues. After 48 hours, however, ice has lost its effect. Using heat after is thought to aid the healing process by increasing the circulation and relaxing muscle spasms. If you have a willing companion, gentle massage may provide some relief by stretching tight muscles and ligaments.