I have swelling in my right hand when I lay down what may be causing this?

Circulation. Swelling occuris with inflamation and trauma, but this would improve at rest. Your symptoms indicate an imblance of circulation of blood or lymph. The change usually comes from structures in the armpit or upper chest. It is an important symptom after breast cancer treatment, and even if a doctor does not appreciate the swelling when you are in the office, pursue answers aggresively.