Ref. No. 41/890
In the name of Allah the most Gracious the most Merciful
The answer to your question is as follows:
The punishment and bliss of the grave is a fact. This fact is well-grounded in Islam through multiple evidences.
The Prophet of Allah (saws) said in a long hadith: . . . . . When the believing worshipper is buried, the grave says to him: “Welcome, make yourself comfortable. Indeed, to me, you are the most beloved of those who walked upon me. Since you have been entrusted to me and delivered to me today, you shall see what I have arranged for you.” It will then widen for him so that his sight extends, and the door to Paradise is opened for him. And when the wicked worshipper or the disbeliever is buried, the grave says to him: “You are not welcome, do not get comfortable. Indeed, to me, you are the most hated of those who walked upon me. Since you have been entrusted to me and delivered to me today, you shall see what I have arranged for you.'” He said: ‘It will begin closing in on him (squeezing him) until his ribs are crushing each other.'” He said: “The Messenger of Allah (saws) clasped some of his fingers between others and said: ‘Seventy giant serpents will constrict him, if even one of them were to hiss on the earth, nothing upon it would grow as long as it remained. They will chew on him and bite him until he is brought to the Reckoning.'” He said: ” The Messenger of Allah (saws) said: ‘The grave is but a garden from the gardens of Paradise, or a pit from the pits of the Fire.'” (Jami al Tirmizi Vol. 4, Hadith No. 2460)
And Allah knows best
Darul Ifta
Darul Uloom Waqf Deoband