Hi Dianne! You may want to see someone about it, if only to rule out things like lymph malfunction or something. Maybe sitting or lying with your arm raised could help with drainage, if that's the problem, but I do recommend having a qualified professional take a look at it, in case it's a sign of something serious.

My right hand tends to get pretty cold from being at the mouse for a long time, but I haven't noticed my whole arm chilling.

Good luck!