Why do you think Heavenly Father would specifically say to you that YOU CAN achieve greatness in His church? Heavenly Father knows you better than you know yourself. He is aware of your shyness. He is aware of the difficulties you face. He wants you to know that you can achieve greatness in His church but you have to know that too. You have to believe in what He has told you and work with Him to achieve that. If you ignore Him how can He help you? It is a great blessing and within your reach and you more than deserve it. Go after it - it will enrich your life in ways that you can't even imagine at this time. Start with baby steps set goals to read scriptures and to pray and build your relationship with God. Give your concerns to him. He will help you. Make it a goal to attend church more often - build relationships. Push yourslef to speak to people. It is hard. When I came back to church I was going through a dark time in my life. I remember going to a church activity and sitting in the car with three strangers and for the whole two hour journey I barely even said one word. I remember a guy saying to me when we were nearly back your really quiet arn't you? I nearly died because I felt so forced to say something but you know what it's ok and it doesn't even matter that much. Even now years on and married I still struggle sometimes with shyness. For me it's a self confidence issue really, always has been, and I just try my best to trust in the Lord and rely on Him. I still panic a bit after church when someone comes over to me to speak to me I find myself praying in my head and thinking crumbs what do I say to them ! but its ok and you know what people arn't too scary