What Causes Sharp Pain Under Left Collar Bone While Breathing?

I started having a sharp pain underneath my left collar bone every time I inhale. The pain started yesterday. I took some aspirin and motrine. After about 5 hours the pain started to die down. In the the middle of the night I woke up with the same pain. It wasn t as strong. Now the pain is less or it s strong. But it hasn t gone away. The pain just came out of the blue. I was standing when it happened.