If it’s not a misalignment in your upper cervical spine, it’s a misalignment in your lower cervical spine. If it’s not that, it’s a misaligned 1st rib. This has been the case for my patients 100% of the time in my 10 year career.
Since this is a fairly common problem for a chiropractor to see (and help with), does it really make sense to use painkillers, steroid injections, or even surgery to deaden the nerves in your arm to deal with the problem? Because those are the usual conventional options.