This has happened to me as well. A lot of times I swear I hear my phone vibrating, even feel it sometimes when I'm at work, or I'll think I'll hear it at home. Song constantly are in my head because I listen to a lot of music. I read somewhere a long time ago about "residual memories", something our brain creates during an event that really isn't necessary as a memory, like sounds we here, emotions we feel, and we'll have the memory so vividly, that we think it's happening right now. The memory of the phone ringing is a memory just like going to the mall with a friend last week. It's not a memory that's necessary but our brain goes, "oh yeah, this is a memory!". I don't remember where I read that. Maybe try searching for "residual memory"