I have to say - I am, at heart, a masochist, and as such, I enjoy painful and uncomfortable procedures.
As others have mentioned, I'm not entirely sure it's the pain itself, or the control that the pain implies, but either way I enjoy it. The unique feeling that comes when a medfet nurse/doctor says "I won't lie, this is going to hurt, but I need you to be still for me and relax. It will be over soon." The intense helplessness that brings on - every muscle in my body, every feeling, every emotion yells and screams 'run!', but I act on none of them, knowing I have to submit myself 'for my own good'. I know there is no way to avoid the pain coming, even as I watch my...torturer....prepare, whether it be a needle and syringe, a catheter, a large speculum, an enema bag, or any other painful instrument. I know that soon I will feel that painful tool used on me, and yet I can do nothing to stop it, but simply lie there, feeling as my pulse quickens, my muscles tighten, and breathing becomes an effort. Finally the pain comes, carefully controlled by the play doc/nurse. The gentleness, but firmness and controlling nature, the dichotomy of care and infliction hit home, as I struggle to endure the painful sensation. Sometimes the pain is over quickly, sometimes not. Sometimes its sharp and harsh, sometimes only dull and soft. Either way, I have no control whatsoever - I need to be examined and treated, and what needs to be done will be done, whether it's 'comfortable' to me as the patient or not.
So yes, I must say, as a patient, I VERY much appreciate pain. I love injections. I love caths and sounds. I love larger specula. I love painful enemas. I need and want to be hurt.
As a playdoc (I'm a switch, and while it's noted that I tend to prefer my role as a patient, since the question asks for insight from either side, I think it important that I answer from both), it's a bit different for me - I relish control more than pain. Some of my patients love pain, others prefer restraint and exposure, others simply the controlling experience of the exam itself. To me, what excites me as a top is meeting my patient's wants and needs, and creating an experience for them - whatever that happens to be. I will say that I tend to enjoy some uncomfortable procedures as a top as well, simply from my understanding as a bottom, and, if I have the right patient, knowing that I have the same kind of control I enjoy so much. There is definitely a rush to knowing what your patient is experiencing, and knowing that you are at the driving wheel - allowing sensation, creating discomfort, playing with embarrassment/exposure a bit, etc. To SEE a patient wince as a device is prepared, knowing that their heart is racing, that their body and mind is screaming for them to run, and watching them lie there for you - that is a thrill in and of itself. To know how excited they are, then push them past that edge.....that can be fun.
So in that sense - I suppose I'm not a true sadist, unlike my masochistic side, in which I actively enjoy receiving pain, I don't directly enjoy giving it; I enjoy the control before I enjoy the infliction, and hence, I play, more often, with those that prefer sensation, scene, and control more than pain and discomfort. And thus, that's probably where my preference toward the role of a patient/bottom comes from.
But each of us is different, and there is not, nor can there be, a right or wrong answer to this. As much as I, as a bottom, enjoy pain, so do others enjoy other topics. Kink is a personal journey - do what makes YOU happy, so long as it is safe, sane, and consensual, and be honest about it. And the great thing about the internet and Zity itself is that you are very likely to find someone who shares your perception of it. When you do, chat it up, and enjoy! 😃