What Causes Dull Chest Pain In A Type 2 Diabetic Patient?

I have dull pain on left side of chest. I have had it for about 5 weeks. It is there all the time. More noticible at times and more intense at others. No tingling in arms. Breathing is fine. Pain does not increase with exercise or raised heart rate. Sleeping and appetite are fine. Pain level maybe 3 to 5. I am a smoker and have type 2 diabetes.