According to TODAY.com, about 3 % of the population will develop a condition called frozen shoulder, which causes pain, arm stiffness and eventual immobility of their shoulder that can last up to two years. Experts aren’t entirely sure why it happens, but it impacts women twice as often as men and there seems to be a hormonal component to it.

“They actually have a name for it in other cultures,” Laura Moore, MD, PhD, sports medicine surgeon at HSS, tells TODAY.com. “In China, they call it the 50-year-old shoulder.”

Frozen shoulder starts with often unexplained shoulder pain that many attribute to an injury and progresses into stiffness that immobilizes the arm completely.

Read the full article at today.com.