I've had this recurring problem where my neck gets covered in red bumps no matter what I shave with and no matter what I put on it. I use clean razors, I put on aftershave, I use witch hazel, I've even bought a shaving cream with aloe but I still get red bumps on my neck and they don't go away. It's ridiculous and I don't know what to do about it.
I used to get bumps as well.
Try cold, cold water on your neck first while rinsing the razor in cold water before starting, then a couple of swipes, then clean it in cold water. The cold makes your pores and follicles close up/shrink back into the skin so you won't touch them. This should preferably be done with a safety razor that has more metal to hold the cold. You might also want to figure out which way different parts of your beard is growing/pointing on your neck, it's not always a uniform direction and you might have a cowlick going without knowing it. It might take a couple of days growth before you can feel it though.
General thoughts:
Hair trimmers are better, less frustrating and much faster than that little thing on electrical razors when it comes to removing anything that is too long for a razor, get one that can cut down to 1-2mm and from there electrical or bladed razors can do the rest. Or just use the trimmer to always have that stubble.
Safety razors are the best and a hot tip for those nervous to use them and cutting themselves, make a fist and hold it so you can see it, shave a knuckle while watching it from the side so that you can see how/where the razor cuts, figure the rest out from there, the motion is a bit different from multiblades because the edge of the blade is in a different place and the bottom is a bit curved instead of flat.
Forearms works for training as well but knuckles have a more curved surface, this is also a good way to test the sharpness of kitchen knives but the motion is that of a straight razor.
Straight razors scares me, maybe because I read The Dark Half as a kid.