I am experiencing sharp, stinging pain in my upper left back, along with aching in the front around the heart area. It isn't going away. What might it be?
One possibility is a herpes zoster infection; we all carry herpes zoster and if it becomes reactivated it can cause that kind of pain and it can be found on the back.
If you see a rash in that area on your back that could possibly be indicative of herpes reactivation....(The rash is not always there...)
If this continues you'll have to see your doctor to get to the bottom of this.
Here are some links on pain management that might be useful:
Why Yoga Can Help Soothe Many Types of Chronic Pain
Using Mindfulness Meditation to Alleviate Physical Pain
Everyday Ways to Protect Your Joints