Took a deep breath and then ever since when i do i get a sharp pain in my neck should i be concerned?

Neck pain: Neck pain which is recreated by certain movements is often from muscle or muscle related injury. A good first step is to try rest, and a heating pad and perhaps some Advil (ibuprofen). An xray and an exam by a doctor are also a good idea.

Pneumothorax?: Your symptoms are somewhat concerning as they are unusual. There is a possibility you may have had a spontaneous pneumothorax. To be on the safe side I would suggest you get an examination and chest x-ray as soon as possible. Going to the ER may be the quickest way to be evaluated. Hopefully, nothing serious will be found. Best wishes.