Asking other people how to become aroused, stay aroused, and have a pleasurable masturbation experience is like asking other people, "what foods taste good?" It's an individualized experience.
Reading your other posts, I think it's important to point out that enjoying masturbation, or any sexual activity, isn't a life requirement. Some people like riding bicycles. I don't like riding bicycles. In the same way, maybe masturbation (or sex) just really isn't for you right now. Most people masturbate in response to something that stimulates sexual desires, so if you're not sure what, if anything, stimulates those desires, it is not likely to be fulfilling to you.
If you do decide to continue trying to masturbate, the only suggestion I have for you is to use a lubrication product intended for sex to avoid unpleasantness from friction.
Not sure what you're question actually means in the achy part. Are you referring to the sometimes ache that results from an erection that lasts a long time? That only goes away when the erection does, one way or the other, if you're going to be walking around while you have one. We have a name for that, but I doubt MedHelp would allow me to say it. If you're talking about achiness from masturbation itself, that just means you're doing it too hard. The above mentions lubrication, but that's only necessary for those who feel the necessity of doing it hard and rough. It's a very sensitive part of the body and doesn't actually need that; it's far more stimulating when it's soft and gentle until you're ready to reach orgasm. As to masturbation itself, it's not something as mentioned above that everyone does a lot. I'm guessing most have done it at least once in their lives, but I never did it until after I started having actual sex with a woman and the relationship ended and I missed what I was getting. Before that, never even considered it. I've managed to get to 68 years old without ever using any kind of lube, so I've never really understood that, I always wonder how you get a good grip that way, but we're all different. As I say, I discovered a lifetime ago that softer was much more arousing and lasted longer and led to a stronger orgasm, but that it's always preferable to do it with someone else you are highly attracted to, though in reality we almost never marry that person. Peace.