left arm going numb and feeling lightheaded

My husband recently had an experience with his left arm going numb and feeling lightheaded for a few seconds. He has had pain in both his left arm and leg for several months, but this is the first time anything like this happened. His legs also hurt at night when he quits moving them. I think he has a touch of restless leg because he is constantly running in bed all night. He is a machinist and is on his feet the majority of the day. Then, the last few days (don't know if this is connected or not) he has this lump that is steadily growing on the left side of his jaw. It started out looking like a pimple does, then it just got bigger and he says it doesn't hurt. It's only slightly red, probably from poking at it. 3 days later is is about the size of a dime. If anyone has any clue to what might be going on, I would appreciate the help. Thanks!