Looking at those quotes from Jesus, I wasn't getting that kind of a vibe from Him. "Whatever you ask for you will receive" does not sound like "sometimes the answer is no"
We must remember that scripture is additive. We should not set doctrine from one passage. You quoted these...
Joh 15:16 Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you.
Joh 16:23 And in that day ye shall ask me nothing. Verily, verily, I say unto you, Whatsoever ye shall ask the Father in my name, he will give it you.
And they are true, but they must be viewed with this in mind...
Jas 4:1 From whence come wars and fightings among you? come they not hence, even of your lusts that war in your members?
Jas 4:2 Ye lust, and have not: ye kill, and desire to have, and cannot obtain: ye fight and war, yet ye have not, because ye ask not.
Jas 4:3 Ye ask, and receive not, because ye ask amiss, that ye may consume it upon your lusts.
Asking to win the lottery is very likely to be unanswered. Another very important point is this...
Mat 6:10 Thy kingdom come.
Thy will be done in earth, as it is in heaven.
1Jn 5:14 And this is the confidence that we have in him, that, if we ask any thing
according to his will, he heareth us:
1Jn 5:15 And if we know that he hear us, whatsoever we ask, we know that we have the petitions that we desired of him.
This is why we fast. We do not fast to cause God to see things our way, we fast to see things God's way...
Isa 58:3 Wherefore have we fasted, say they, and thou seest not? wherefore have we afflicted our soul, and thou takest no knowledge? Behold, in the day of your fast ye find pleasure, and exact all your labours.
Isa 58:4 Behold, ye fast for strife and debate, and to smite with the fist of wickedness: ye shall not fast as ye do this day, to make your voice to be heard on high.
Isa 58:5 Is it such a fast that I have chosen? a day for a man to afflict his soul? is it to bow down his head as a bulrush, and to spread sackcloth and ashes under him? wilt thou call this a fast, and an acceptable day to the LORD?
Isa 58:6 Is not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke?
Isa 58:7 Is it not to deal thy bread to the hungry, and that thou bring the poor that are cast out to thy house? when thou seest the naked, that thou cover him; and that thou hide not thyself from thine own flesh?
Isa 58:8 Then shall thy light break forth as the morning, and thine health shall spring forth speedily: and thy righteousness shall go before thee; the glory of the LORD shall be thy rereward.
Isa 58:9 Then shalt thou call, and the LORD shall answer; thou shalt cry, and he shall say, Here I am. If thou take away from the midst of thee the yoke, the putting forth of the finger, and speaking vanity;
Isa 58:10 And if thou draw out thy soul to the hungry, and satisfy the afflicted soul; then shall thy light rise in obscurity, and thy darkness be as the noonday:
Isa 58:11 And the LORD shall guide thee continually, and satisfy thy soul in drought, and make fat thy bones: and thou shalt be like a watered garden, and like a spring of water, whose waters fail not.
Isa 58:12 And they that shall be of thee shall build the old waste places: thou shalt raise up the foundations of many generations; and thou shalt be called, The repairer of the breach, The restorer of paths to dwell in.