Why is rubbing alcohol good for pain?

Topical, right? I am assuming you mean topically during massage. Rubbing alocohol can do a couple of things to help get a massage deeper into muscles or relax them. First, the temper change and sensation on nerve endings in your skin can help muscles relax. Second, the alcohol acts as a varying lubricant on your skin that changes through out the massage that allows different pressure. Hope this helps!