Prayer is not easy. I find that true myself, but others whom I respect have also given testimony to the difficulty of prayer. Some chaps make it sound easy; if they spend hours a day in the tent of meeting, they probably have their computer in the tent with them.
Consider the following testimonies, which are filled with thoughts that one ordinarily doesn't hear when people give their public testimonies, oddly enough:
"Everything we do in the Christian life is easier than prayer." Martyn Lloyd-Jones
"There is nothing that we are so bad at all our days as prayer." Alexander Whyte
"There are times in my life when I would rather die than pray." Thomas Shepard
Imagine Thomas Shepard saying those words as he is brought to the front of the church to "speak about the wonderful things God has done in his life." Whatever the case, I find those words from the aforementioned men somewhat comforting. In fact, read this from John Bunyan:
"May I but speak my own Experience, and from that tell you the difficulty of Praying to God as I ought; it is enough to make you poor, blind, carnal men, to entertain strange thoughts of me. For, as for my heart, when I go to pray, I find it so reluctant to go to God, and when it is with him, so reluctant to stay with him, that many times I am forced in my Prayers; first to beg God that he would take mine heart, and set it on himself in Christ, and when it is there, that he would keep it there. In fact, many times I know not what to pray for, I am so blind, nor how to pray I am so ignorant; only (blessed be Grace) the Spirit helps our infirmities [Rom. 8:26]."
That's a Puritan - ahem - who obviously struggles, as most of us do, with prayer.
Sometimes Christians get in a "prayer rut" and find it difficult to break out of that rut. It isn't that they give up praying altogether, but they do seem to give up spending time alone with the Lord in what the Puritans called "private, fervent prayer" (see Heb. 5:7).
Of course, there is no rule set down how often and how long we should pray. Yet, we pray without ceasing (1 Thess. 5:17); we are to pray at all times (Eph. 6:18); and we pray suddenly based on need and occasion (Neh. 2:4).
The Bible also gives us examples of those who seemed to have set times or specific times where they devoted themselves to prayer (Matt. 6:6). Consider Daniel, who prayed three times daily, "as he had done previously" (Dan. 6:10). "Peter went up on the housetop about the sixth hour to pray" (Acts 10:9). And our Lord Jesus "would withdraw to desolate places and pray" (Lk. 5:16).
Given that prayer is difficult, how does Christ motivate us to pray? In Matthew 6:6 he promises his disciples their Father will reward them for what they do (i.e., pray) in secret. Notice how often the word "reward" appears in that chapter alone.
We do have to ask ourselves whether we adequately believe the words in Matthew 6:6. Do we really believe, as we should, that God will reward us? If we did, we would indeed spend a lot more time in secret prayer than we do. We do not have because we do not ask! We do not ask because we lack faith (Matt. 21:22).
Faith is the hand that begs from God: "And without faith it is impossible to please him, for whoever would draw near to God must believe that he exists and that he rewards those who seek him" (Heb. 11:6).
Christ, the man of faith par excellence, certainly grasped this concept in his own prayer life. In fact, he prayed for his reward: "And now, Father, glorify me in your own presence with the glory that I had with you before the world existed" (Jn. 17:5).
I don't know precisely how the Lord will reward us for what we do in secret. Sometimes the answers to prayer are either obvious or immediate. Sometimes he rewards us by not giving us what we (sometimes wrongly) ask for. And there are prayers which may not even be answered in our own lifetime (see Stephen's prayer in Acts 7:59-60, which may have resulted in the conversion of Saul of Tarsus; or notice how Moses' prayer to see God's glory in Ex. 33:18 was answered at the Transfiguration).
But I do know this:
The rewards from our Father are of grace: "It is called a reward, but it is of grace, not of debt; what merit can there be in begging?" (Matthew Henry)
And, he has promised to reward his children when they pray in secret, and that motivation alone should be enough to get us into our "prayer closets" where we ask in order to receive.