Our Scripture reading today is Luke 18:2-5.
Verse 5, "Yet because this widow troubleth me, I will avenge her, lest by her continual coming she weary me."
The parable of the unjust judge and the widow shows us the exact opposite of how our Heavenly Father responds when we pray.  It is very clear in Scripture that God wants us to pray and He wants to answer our prayers.  We are not bothersome to God when we are bringing our petitions to Him.  Our persistence in prayer is not because God does not want to answer but because He does want to answer.  Why is there a delay in answering our prayers?  I truly believe it is not about changing God's mind on the matter, but it is about God changing me.  I need to grow in grace as I am praying for God's will on a particular matter.  I may need to bring my will in line with God's will.  Whatever the reason, God loves me and is doing a good work in me.  
Keep praying and seeking the will of God and you will see His working in a clear and mighty way!