Nokia 6620

I just got my phone for about two weeks now. I found a software to convert mp3's and mpeg/avi to .awb and .3gp so that i can use mp3 songs as ringtones on my phone. About 2days ago i noticed that my phone was making a strange irritating loud background noise anytime it rings or anytime i play any media file i saved on it. I don't know what the problem is or how to correct it. I need help cuz it's really freaking me out. would appreciate it if someone can help me out on what to do.