My husband had the "sore back", "heart attack" feelings when he had a problem with heartburn. It turns out that the same nerves that are connected to your chest area that can become irritated from heartburn, also radiate outward and wrap around to your back as well. He went to a chiropractor who detected a displaced vertebrae that was connected to the bad digestion. I know it sounds crazy, but that's what it was. If you can't find the cause thru a medical dr. I would go see a chiropractor that uses the "Gonstead method". Those pin ***** feelings also sound like nerves to me.
I've had this for many years. In my case, it was mere anxiety. But, as far as I can tell, it can also be a problem with the circulation of oxygen in your blood, a "twisted" nerve, vitamin deficiency; the list goes on. Your best bet is to visit a neurologist.