When you hurt everywhere, Muscle pain in a small area of your body is usually caused by overuse. For example, if you lift boxes all day, your arms might hurt by the end of the day. Or it could be something small, like a sprained shoulder from tripping. But if you hurt all over, it's probably because you have an infection, sickness, or are taking medicine. Trouble with Blood Flow If your arms, legs, or both hurt, it could be because your muscles aren't getting enough blood. This is called claudication. At first, you might only feel it when you work out, but after a while, you might feel it when you sit or walk. This is generally caused by arteriosclerosis, which is when the blood vessels that bring blood to your muscles get clogged up. Hypothyroidism This is when your thyroid gland doesn't make enough of certain important hormones. It can make muscles and joints hurt and cause swelling and sensitivity. It can make you tired and cause problems with your memory, hair loss, dry...