Fasting is one of the greatest acts of worship and one of the best means of drawing close to Allah. Al-Bukhaari (1904) and Muslim narrated that Abu Hurayrah (may Allah be pleased with him) said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Allah says: ‘Every deed of the son of Adam is for him, except fasting. It is for Me and I shall reward for it. Fasting is a shield, so when it is a day when one of you is fasting, let him not utter any obscene speech that day or raise his voice. If anyone reviles him or tries to fight with him, let him say: I am a man who is fasting. By the One in Whose hand is the soul of Muhammad, the smell of the mouth of the fasting person will be better before Allah on the Day of Resurrection than the fragrance of musk. The fasting person has two moments of joy that he enjoys: when he breaks his fast he rejoices, and when he meets his Lord he will rejoice because of his fasting.’”
This clearly points to the great status and importance of fasting in the religion of Allah, and to the virtue of those who fast and the greatness of their reward.
Shaykh Ibn Sa‘di (may Allah have mercy on him) said:
These are two rewards, one in this world and one in the Hereafter.
The reward in this world is seen when the fasting person breaks his fast; he rejoices in the blessings that Allah has bestowed upon him by enabling him to complete the fast, and he rejoices at fulfilling his desires that he refrained from during the day.
The reward in the hereafter will be his joy when he meets his Lord and He is pleased with him and honours him. This later joy is a reflection of the earlier joy in this world, for Allah will grant both to the fasting person.
It also indicates that when the time of breaking the fast comes near, and the fasting person experiences this joy, it is in return for what he has endured during the day of the hardship of forsaking his desires. This comes under the heading of encouraging and motivating the individual to do good.
End quote from Bahjat Quloob al-Abraar, 96. See also: Fath al-Baari by Ibn Hajar, 4/118
Hence you will find that the Muslim for whom fasting is difficult but he is able to put up with it rejoices at the time of breaking his fast, not because the difficulty has ended but because Allah may He be exalted, has helped him to put up with it and complete the act of worship to Him, may he be glorified. His focus was not on the hardship, waiting for relief, rather his focus was on the act of worship and his determination to complete it. According to the saheeh hadeeth narrated by Abu Hurayrah, the Prophet (blessings and peace of Allah be upon him) said: “Would you like to strive hard in du‘aa’ (supplication)? Say: Allahumma a‘inna ‘ala shukrika wa dhikrika wa husni ‘ibaadatika (O Allah, help us to give thanks to You, to remember You and to worship You properly).” Narrated by Ahmad, 7922; classed as saheeh by al-Albaani in as-Saheehah, 844.
You can hardly find anyone who feels distressed during this blessed month, except those who are more concerned about worldly matters so that they may indulge in desires and pleasures, and do not like to keep away from them.
The one who encounters hardship and tiredness because of fasting is one of two types:
Either he has an excuse, such as sickness, travel and the like, in which case he may avail himself of the concessions granted by Allah and break the fast;
or he encounters bearable hardship, so he completes his fast and is patient in putting up with this hardship, seeking the pleasure of Allah.
As for the one who encounters hardship and dislikes fasting, and wishes that the month would end and never come again, this is undoubtedly inappropriate; this is a person who dislikes worship and is not patient in adhering to the commands of Allah.
For more information, please see the answer to question no. 13480
And Allah knows best.