Re: Tingling...what does it mean?
I wouldn't be particularly concerned at this point, but keep an eye on it. Tingling is a sign that something is disturbing a nerve. The area of the spine that you are describing is the thoracic area and the nerve patterns in that area run in a band around the core. It is possible your wife has strained a muscle in her back, which has irritated a nerve. She might want to take a NSAID for a couple days in case there is any inflammation and restrict her arm movements so she isn't reaching up overhead or to the side to see if that helps.
Keep in mind that spine "issues" while extremely painful are almost never a medical emergency. Your wife has plenty of time to see if this will heal and go away on its own. If the pain increases or she becomes concerned, there will be time to see a doctor. She may have done something as simple as sleeping with her neck in an awkward position.
If she suddenly develops pain in her chest, you should call the doctor as it may be related to an organ in her chest, like the heart. Pain from an impending heart attack can be located in the shoulder, arm, etc. so don't take any chances if something in addition to the tingling develops.