I have been getting intermittent pain around the lower left breast line that extends to left most side of the breast. sometimes causes shoulder pain and jaw numbness. ekg and echo normal. no high bp, border line cholesterol. what could it be?

Is the pain present all the time? This could be due to chest wall pain. The chest wall has bone, cartilage, muscle and any of these components can cause pain. Sometimes, the cartilage becomes inflamed and causes a condition called costochondritis. The treatment for that is typically NSAIDS, like ibuprofen. If pressing on your chest reproduces the pain, it is chest wall related. Good luck!