Can I submit a paper to two or more journals at the same time? Assume I am submitting my paper to Journal X, which rejected the paper. After making modifications I am going to submit the paper to Journal X again. At the same time can I also submit the paper to another Journal Y (which has a lower impact factor than Journal X). As the Journal X has rejected it the first time, I think it may be rejected again. So I want to publish my work anyhow in a journal.
No, not the same paper in two journals at the same time.

Either submit to X again or submit to Y.