What Causes Pain In The Breast On Taking A Deep Breath?

Hi, Last evening I woke up with severe pain in my left breast which kept me awake from 3:00 am until I finally got out of bed at 6:30... I was unable to take a deep breath and it hurt when I coughed ..... it was the strangest occurence I have ever experience and the first time it has ever happened. Today I can breath without discomfort and have not experienced any pain ???