Of course it's difficult. That's what makes it so valuable.
The time, effort and commitment you put into reaching the goal have their own rewards, over and above the achievement itself. They make you stronger, more disciplined, and more effective.
When great effort is called for, great opportunities abound. When challenges and difficulties surround you, there is much value to be created.
Instead of cursing the need for sustained and focused effort, be genuinely thankful for the chance. For you are designed and equipped to get things done, and life is superbly rewarding when you do.
When difficult work is called for, step quickly forward with enthusiasm. It is truly your moment to shine, to grow, and to create according to your best expectations.
Run toward the challenges. It is in those challenges that you will fulfill your greatest dreams.