I am trying to publish my first research paper but facing difficulties. I am a newbie in the research world. why is it so hard?

It depends on which journal you want to publish your paper. If you just want to have publications then there are many paid journals available where you can publish your paper easily. But it's better to publish in a journal that has a high impact factor. To know about a journal look at its SJR ranking or ISI Impact factor or the publisher like Elsevier, Springer, ACM, IEEE, IET, Wiley, Taylor and Francis. If you mean to publish in ISI Q1 , Q2, Q3 journals then it's really not that easy.

There are several reasons for that. Check this link.
https://www.elsevier.com/?a=91173