My son, age 18, has been complaining of his forearms and hands falling asleep often for the past few weeks. It started (this time) when he began doing hard physical labor--lots of shoveling. It happens while he's working, and lots of times when he's sleeping. Sometimes his arms get swollen during his sleep. What could be the cause and what are remedies/treatments he should consider. He is strong and otherwise in great health. He is 5' 9" and weighs about 155 pounds.