A CT isn't the best imaging test for this (unless a specialist is adamant about it), because CTs have much worse resolution than MRIs, and involve x-ray radiation, so if you don't need a CT and an MRI
would do as well or better, go for the MRI
. You could have damaged the shoulder, which is now pinching the nerve, or you could have injured your neck, which could also cause nerve pinching. Getting it sorted out quickly is important.