By paid journal, do you mean you, the author, gets paid for the paper you submitted?
Research Journals I know are all journals that required paid subscription. Usually, institutions subscriping to these journals for their libraries have to pay the publishers. These are also journals that researchers submit their papers for publication.
Of course, the authors are not paid, but the reward for their contribution is for their paper to get published, which is the hope and dream of all researchers. Unless, your paper gets published, which is highly competitive, in reputable research journals, nobody will get to read your research and your contribution to extant literature.
So, to answer your question, it is normal and OK to submit your paper to a paid journal. As noted, no monetary payment is made to you as the contributor.