Astral from my POV is a completely different realm and isn't "a jumping porthole" situation as you describe. Lucid, Mental, Dreaming, Regression are all in as we see 3D normal colour schemes (except if you want to get technical i'd say the world has a hard light effect about it, similar to a solar eclipse) where when I astral it's multi-visual-dimensions and a UltraViolet colour scheme.
I find people who force their dreams are the ones with the worst experiences doing so. Like your psyche is punishing you for forcing your way in.
From a dreaming aspect, you have probally had a traumatic experience within health. Either as a child with hospitals, doctors, dentists (most of the time is because you go into the room by yourself) or you have had a family member / close friend have major complications with the same and you felt you were behind closed doors about the situation.
My tips are play with your lucid then your astral then your regression.
Lucid - Dream about a place you would like to see, an object you would like to have/play with or Someone you wish to see.
Go to sleep with good intentions and keep this on your mind. Rather easy and harmless to play with, it's conditioning for control in the other realms. Keep in mind try to stay in control of yourself and the chosen situation everything else treat like a sandbox.
Astral - TBH I have never forced it, I am taken to what is being presented. From what I was taught if you wanted to see a particular place/town/object/country ponder about it before sleep, this is different from how you think in Lucid, Lucid is forcing something to appear where astral is your soul taking you. I usually find myself in Egypt near The Sphynx or in jungles that I could only presume is The Amazon. In lamens terms, think Habbo hotel but trippy. I have met and chatted with a few (2 or 3 not a whole lot) people while doing so but once again never under "OMFG I HAVE TO GO TALK TO THAT PERSON" premise, more so we happen to float near eachother. But it is, what it is Travelling of the Soul. I don't see why so many people are interested in making Astral Travel do other than it's purpose, I usally put it to the person having a control issues in life so they try to force control where they feel in power to balance it out. You'll just keep lucid dreaming and that's when your nasties will come to screw with you... you are trying to screw with their world in hindsight so it's in my eyes kharmic (You'd be pretty annoyed with someone telling you to use deorderint for mouth wash (kinda similar but way different). I love and adore how everything is presented in a multideminsional tranlucentness and the landscapes I wake up feeling feeling like coming back from holidays.
On the quirky sides of things, ever woken up and feel like you've hit the bed and bounced awake. That in my teachings and pov is your soul just catching your body waking up.
Regression - Aaah, the big boy out of the 3. This is where it can get dangerous. This is usually the presumption of what astral does in the way of what people are looking for. This place is interesting because it's a Place dedicated to you and your past lives. Containing everyone you have ever met, throughout every life you have lived. (We tend to stick in the same groups when it comes to reincarnation). This is the information source of everything to do with you and people have been known to pick up skills in this realm; Language, Trade, Arts. Be warned though it can be harmfull if you start talking to the wrong people. Key is though if you do not feel safe with a person or surrounding ask it to leave.
If you don't mind otkbrat what teachings or followings do you represent in yourself?
If you are not open to the concept of a soul, afterlife, different realms, spirits, reincarnation and belief in possibility of any of it happening. You will just be running around in circles. It'd be like a complete atheist sitting in a church. For what purpose other than a wolf wearing sheeps clothing. Mind IS over Matter.