i do not know if you have been diagnosed with rsd, but in general yes, if your nervous system does not tell your body to pump fluid and blood in the proper way, then you get a pooling of those fluids and thus swelling. also if your nervous system is sending the wrong messages about if there is or is not pain, or how much pain, then you get the wrong signal and feel intense pain where there should not be intense pain. rsd is basically a screwed up signal system. with you, if your arms are hanging down in any way, this encourages the pooling of fluids, and things like opening and closing your finger and hands can help get things moving. i don't know if i've helped but that is the simplest way i can explain it all .... and even at that, and with years of reading, it never truly makes sense. joan