High-energy electromagnetic radiation traces the hot and energetic phenomena occurring in the Universe. It probes the 'hot' gas in galaxies and clusters, as well as the 'energetic' accretion flows around compact objects and supermassive black holes. The key questions in astrophysics are related to understanding the nature of these accretion flows around compact objects and supermassive black holes, and how they influence the formation and evolution of large-scale structures. In this talk, I will present results from investigations into understanding these accretion flows and how the feedback from them affects the distribution of hot gas in galaxies. Finally, I will mention future plans related to understanding these hot and energetic processes with the current and next generation of multi-wavelength observatories.