What Causes Left Sided Chest Pain?

I have been experiencing chest pain. It started in the soft spot right under my sternum. First, I was having palpitations, then pressure would start to grow. Now I am experiencing pain on the left side of my chest right above the breast. It feels like a sharp steady pain. Comes on a few times a day. This has all developed in the past two months. I do not have enough money, even with my health insurance, to go to the emergency room. I do not smoke or drink. The only medications I am on are Birth Control pills. I've been taking them for four years. For the past year I have been on Yaz. Is this serious or just a muscle pain?Any help would be greatly appreciated!