For a few weeks now I've had pain under my armpit to the aide of my chest up to the top part of my breast its more on the right but sometimes on the left. The pain is also in my shoulder and my face is numb. What can it be??

Also have really bad headaches

It's time to see a Dr. There's no way we can diagnose this for you.

It is your body telling you to see a Doctor. Quickly. Like make an appointment today, for today. Any unknown pain in your chest should be checked out quickly. It could be a sign of organ failure or could just be a pulled muscle. Do you want to chance it? That being said you can't give us enough information to possibly know what is going on. To make a diagnosis would be foolish and dangerous.

Go to a doctor.