Typically because of unconfessed sin, if you have unforgivness in your heart, that alone can render your prayer life dead on arrival. you must also be willing to hear from the Lord, sometimes people only want to hear a certain way. Remember God can speak to you through your circumstance, people, your thoughts, dreams etc. Its up to you to have a heart to listen.
Matthew 6:14-15
14 For if ye forgive men their trespasses, your heavenly Father will also forgive you:
15 But if ye forgive not men their trespasses, neither will your Father forgive your trespasses.
Jeremiah 29:13
13 And ye shall seek me, and find me, when ye shall search for me with all your heart.
Luke 11:9-13
9 And I say unto you, Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you.
10 For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.
11 If a son shall ask bread of any of you that is a father, will he give him a stone? or if he ask a fish, will he for a fish give him a serpent?
12 Or if he shall ask an egg, will he offer him a scorpion?
13 If ye then, being evil, know how to give good gifts unto your children: how much more shall your heavenly Father give the Holy Spirit to them that ask him?
Revelation 3:20-22
20 Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me.
21 To him that overcometh will I grant to sit with me in my throne, even as I also overcame, and am set down with my Father in his throne.
22 He that hath an ear, let him hear what the Spirit saith unto the churches.