It seems that only someone who had experienced death can answer that; and, then their answer could only reflect their own personal experience. It seems logical that each person will have their own unique experience when their time comes to die.
While I've not yet truly died, I've almost died three times. Each time I felt some level of pain, but nothing more than I could handle... and then the pain subsided as my brain began to hallucinate. While I still felt pain, it didn't bother me as much. You see, during those moments before I was brought back from the brink of death, I was only vaguely aware of my surroundings... my hallucinations captured my interest instead of all the frantic business happening around me and I remember feeling OK with passing away.
In only one instance did I feel completely outside of my body, I was told that I had lost consciousness from severe blood loss and oxygen deprivation to my brain, but it seemed to me that I was conscious... watching what was happening to my body from a nearby view point. But, I was not in any way feeling anxious or upset; in fact I had no compulsion to return to my body... I remember feeling as if I was free. This particular instance was when I was bleeding to death. I had lost so much blood that I required 6 units of whole blood and 4 more units of plasma. I am a small person and am told that I probably cannot hold anymore than 7 units total. (I'm 5'4" and weight about 107 lbs)
It took some time to get the artery in my liver to stop bleeding and to stabilize my heart and oxygen levels. But I do remember the very moment I 'returned' to my body and regained consciousness... I remember that I cried like a baby because I was in unbearable pain. For the next couple weeks while I healed, I had wished that I had died. Of course, now I am glad to still be alive.
The other two times I was in the process of losing consciousness, but never fully did and never felt like I 'left' my body, instead I had visitations from people that no one else saw or acknowledged... perhaps I dreamed them up like when you are having a realistic dream just before it is time to wake up from a full night's sleep.
In both those cases, I was in pain, but I don't remember it being intolerable, just annoying and uncomfortable. I remember feeling like it was difficult to breathe and I was aware that my heart was beating very rapidly, but faintly, weakly. I was not scared of dying in any of these experiences. I accepted whatever would happen next. I remember feeling pity for my husband and an overwhelming love for him... so I tried hard to hold on for him and our children.
I think it does to hurt to die in the beginning of the process, but once your mind accepts the fact that you are actively dying, that your organs (including your brain) are shutting down, it ignores the pain and it isn't so bad. Maybe someone else could tell about their personal experience with recovering from the brink of actual death.
We can never know what someone else's death feels like to them, we can only guess from how they look and behave while they are dying, but how can we truly know if they are hurting or not.