muscle/skin crackling and bubbles

When I rub my neck, upper back, arms, that whole area there is a sound like slowly crinkling paper or pop rocks. I can also squeeze my arm down from the top and see huge air bubbles or something like that travel through my veins and/or around them until it gathers into a big bubble at my wrist. As I do this I can feel the pressure build in the veins and it hurts. Is this edema or something more serious? I'm very underweight, but have never had this symptom before. I appreciate any help you can give me. Thanks.