Is it possible that you could be a good singer and a microphone can make you sound bad?
Absolutely. There are settings on an amplifier or mixing console that completely alter the quality of the tone as it is amplified. You need to adjust the frequencies, often things like “Reverb,” “Echo,” “Delay,” “EQ,” “Bass” or “Mids.” Also, sometimes the speakers in an amplifier or sound system are not very good in which case there is not much that can be changed. Another variant is the quality of the microphone. If the microphone does not pick up all of the frequencies it can strip the sound. If it picks up room noise as well it can distort the sound. See if you can work with a sound engineer to learn about the different effects and what works best with your voice. You can also just go to a music store and try out mikes and sound systems, getting the sales person to explain things to you.