I graduated in physics from Bangladesh and keen to work in the field of biology. Like, systems biology, computational biology, bioinformatics or systems medicine. I have not produced any research work in such fields as of now. I am studying sequence alignment and RNAseq and later plan to study flow cytometry bioinformatics. I have no affiliation with any institute now in my country as they don't accept students from other disciplines. Is it possible for me to do research on my own by using databases available? If so, I would be really grateful if anyone can suggest how to approach my research topic/work.
Doing actually valuable bioinformatics research completely on your own after graduating from university (I am assuming that this corresponds to a master's degree) is somewhere between impossible and very unlikely - even for someone who actually studied bioinformatics.
In order to really do research (in almost any field) you will have to become a PhD student first - and for that studying the relevant topics on your own, like you are already doing, is probably the best preparation.
If there are truly no 'cross discipline' applications possible where you are from, you'll probably have to apply for programs or positions abroad. It is, however, becoming increasingly common for bioinformatic research groups to hire people from various different backgrounds - ranging from wet lab biology to physics. I would advise you to actively look for such interdisciplinary research groups (ideally purely computational groups as a physics background will be more valuable there than in a mixed dry/wet-lab group) and potentially directly contact the group leader if the university/institutes don't offer any programs that would allow you to apply.