This may have nothing at all to do with my surgery, but it started not too long after I had my RNY.  In the space between my shoulder blades, I get a wierd, numb, tingly sensation. At first it would really bother me - even my shirts rubbing against it would almost hurt.  I think I have gotten a little used to it....I was going to mention at my next Dr. appt....but yesterday I was outside for awhile at a company picnic, and all of a sudden I got a sharp, stinging sensation in the exact same area. I thought for sure that I had been stung by a bee (or two, or ten!)...but nothing was there. The stinging went away after about 10 minutes.  Now tonight, coming in the house from the grocery store, same thing happened. A sharp stinging pain. My husband was right there, and he looked. He said that the area was red, but no bumps or signs of any bites/stings.

I never felt this sensation until after my RNY, but it could have nothing at all to do with it. My B12 was in the 500's in June when I had my bloodwork, but I take 1000mcg every day...and 3-4 times per week I am taking 2000 mcg per day.  I am not having unusal numbness anywhere else. This is just such a strange sensation that it is hard to explain....it's numb but it hurts at the same time.  

Any ideas? 

Pinched nerve?

a b12 level in the 500's is dangerously low for us but doesnt' usually present with numbness or tingling in the neck but it usually presents in the feet, toes, fingers or hands.  I guess it is possible.  You really need to increase your B12 significantly because B12 levels below 500 put you at risk for nerve damage and that was your level in June, so you don't know if it went up or down since then.  I would increase your B12 to 5000mcg daily for 6 weeks and then get rechecked.  We want our levels to be between 1200-1800 but there is no danger in being higher.  We just pee out the excess but being deficient is very danger.  IF left deficient for too long, it leads to nerve damage and it can become permanent.

If it isn't due to your low B12 levels, it could be from a spinal problem.  I have herniated discs in my neck and get similar numbness and pain in my neck.

 Pinched nerve or something musculoskeletal is what my surgeon said when I saw her last week. I had very similar symptoms, just in reverse. One morning I was troubled with some stabbing pain in the middle of my back near my right shoulder blade and it hurt like someone was stabbing me every time I turned my back or neck but would go away if I stayed still. I put some heat on it and took some Tylenol and it got less and less over the next several days. 

I have experienced similar pain in that area and it was suggested that my posture is adjusting to not carrying the extra weight around. It acts up when I am walking and looking down or driving for too long and eases up when I straighten up and pull my shouldes back.

This is exactly how my heart attack started. If your husband hadn't said the area is red, I would be calling 911 right now.
It could be a pinched nerve or even a torn rotator cuff. You were lying totally immobilized on an operating table for a long time. Your body is also adjusting to carrying you differently. See if you can pinpoint what you were doing for a few hours before this happenend. I bet there is a pattern.