Experiencing really bad right chest pain...?

Today in the morning my husband step outside for a while to get some air and it was a little chilly. He cam back in where it was warm and decided to wash some pants by hand with cold water. Just a few minutes later,he started saying his right side chest was hurting badly. Well more like his right whole side. Its been like this all day. When his laying down it feels fine but as soon as he gets up, he feels the pain get worse. What could it be?Should he be worried?