I don't know Im looking myself I have the same issue. Left blade and whole patch around it is numb on the skin and from time to time I get large shoots of pain inside. Like im being stabbed

Iv had it for awhile on the skin but the pain has just started to get worse

Could be a pinched nerve, but if you are concerned have it check out with your doctor...

Caroline

I have similar problems. When mine started I was at the gym and felt a sharp burning underneath my left arm while working out as well a very sharp pain in the left side of my neck. That evening, the skin around my armpit to my back and then also to the front close to my chest was numb. Also under my arm and armpit was numb too. I woke up the next morning and the pinky on my left hand was numb. The more I moved my arm, the other fingers would start going numb.
I was also in a car accident 6 months prior suffering severe whiplash after being hit from behind.
The Chiropractor and Massage Therapist told me that it is a combination of 2 things. A pinched nerve in the neck and being that my muscles were extremely irritated, that would cause the numbing in the other areas.
I suggest seeing a chiropractor regarding this as they are specialists with the nerve/spine/joint areas.
Hope this helps )

K