I have a tingling and sometimes aching feeling on my back, right about under my shoulder blade. what could it be?

Unlikely: Shoulder blade pain or scapulathoracic pain is usually musculoskeletal related. Stretch-grab a door frame lean back and then rotate toward your arm so that you put a stretch on the area and hold for 10 plus seconds. Do this several times a day. Apply heat. Lastly, massage the area by putting a tennis ball in a stocking, put it on the area and lean against a wall and roll the ball on the area.