About God's silence, I have found He is often silent when I ask Him about something that is already in the Bible. And no, I don't mean sin specifically, although it IS rather futile to ask Him if it's okay to do something the Bible already said is wrong. I mean the Bible covers a whole lot of stuff - it's basically a user manual for the body and the world we are in.
About joy, that is inseparable from all the other facets of a relationship with God - peace, love, faith, when one increases they all increase. When one decreases they all decrease. Usually it is faith that increases or decreases first. As I trust God more, I have more peace. As I have more peace, there is more room for joy in my life. As I have more joy, I love God more. And as I love God more, I have more faith in Him. The circle can increase or decrease, but it never stays static.