I am having severe pain side of my left breast it pains even more if I cough and it's a dull pain through out the day it's been a week since I am done with my periods and I do not see any lump or redness but there is an extremely sharp pull even if I cough slightly or if I move my arm , this has been there since the last two weeks and hasn't improve the pain is radiating from left shoulder till side of left breast . What could this be ?