1 Service Details Priority Mail ExpressÂ® Overnight Guarantee1 Delivering 7 days a week, this is our fastest domestic service for time-sensitive letters, documents, or merchandise. 2  Guaranteed overnight scheduled delivery to most locations2, including PO Boxes, or your money back1. 3  From $13.09 online.
Freebase(4.82 / 22 votes)Rate this definition: Muscle pain. Myalgia, or muscle pain, is a symptom of many diseases and disorders. The most common causes are the overuse or over-stretching of a muscle or group of muscles. Myalgia without a traumatic history is often due to viral infections.
What are muscle cramps? A muscle cramp is a strong, painful contraction or tightening of a muscle that comes on suddenly and lasts from a few seconds to several minutes. It often occurs in the legs. A muscle cramp is also called a charley horse. Nighttime leg cramps are usually sudden spasms, or tightening, of muscles in the calf. The muscle cramps can sometimes happen in the thigh or the foot. They often occur just as you are falling asleep or waking up. The cause of muscle cramps isn't always known.