Most people experience occasional musculoskeletal pain, which is pain in the muscles, joints, ligaments, and tendons. For instance, you may get sore muscles or achy joints after exercising or doing yard work. The pain usually goes away after you rest or take an over-the-counter pain medication.But when is pain a sign of trouble?"Not all pain is the same, and it should never be ignored if it begins to affect your daily life," says Dr. Mohammed Issa, medical director of the pain management center at Harvard-affiliated Brigham and Women's Hospital. "While some temporary pain is normal, it's never normal to live with pain."