Can you have an all of a sudden sharp gas pain in upper arm....

Gas pain.: A gas pain could potentially refer upwards, but I wouldn't assume that a gas pain would be located specifically in your upper arm. I would entertain other possibilities.

That's not possible: You can have a sharp sudden pain in your upper arm from a muscle spasm, or spastic muscle, but gas pain is usually in the gut area, not arm. However, if you have a bad infection involving cellulitis, and is becoming swollen, abscessed and worse in your skin in your upper arm, then you need to seek immediate drainage of the abscess that could appear with discharge or gaseous, depending on the cause